Swing adsorption processes using zeolite structures

ABSTRACT

The present disclosure describes the use of a specific adsorbent material in a rapid cycle swing adsorption to perform dehydration of a gaseous feed stream. The adsorbent material includes a zeolite 3A that is utilized in the dehydration process to enhance recovery of hydrocarbons.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of and claims priority to U.S. patentapplication Ser. No. 15/669,161 filed Aug. 4, 2017, which claims thebenefit of U.S. Provisional Patent Application 62/382,544, filed Sep. 1,2016, entitled SWING ADSORPTION PROCESSES USING ZEOLITE STRUCTURES, theentirety of which is incorporated by reference herein.

FIELD

The present techniques relate to rapid cycle swing adsorption usingzeolite structures. In particular, the zeolite structures may be used inprocesses for separations, such as swing adsorption processes and systemto enhance recovery of hydrocarbons.

BACKGROUND

Gas separation is useful in many industries and can typically beaccomplished by flowing a mixture of gases over an adsorbent materialthat preferentially adsorbs one or more gas components, while notadsorbing one or more other gas components. The non-adsorbed componentsare recovered as a separate product.

By way of example, one particular type of gas separation technology isswing adsorption, such as temperature swing adsorption (TSA), pressureswing adsorption (PSA), partial pressure purge swing adsorption (PPSA),rapid cycle pressure swing adsorption (RCPSA), rapid cycle partialpressure swing adsorption (RCPPSA), and not limited to but alsocombinations of the fore mentioned processes, such as pressure andtemperature swing adsorption. As an example, PSA processes rely on thephenomenon of gases being more readily adsorbed within the porestructure or free volume of an adsorbent material when the gas is underpressure. That is, the higher the gas pressure, the greater the amountof readily-adsorbed gas adsorbed. When the pressure is reduced, theadsorbed component is released, or desorbed from the adsorbent material.

The swing adsorption processes (e.g., PSA and TSA) may be used toseparate gases of a gas mixture because different gases tend to fill themicropore of the adsorbent material to different extents. For example,if a gas mixture, such as natural gas, is passed under pressure througha vessel containing an adsorbent material that is more selective towardswater vapor than it is for methane, at least a portion of the watervapor is selectively adsorbed by the adsorbent material, and the gasexiting the vessel is enriched in methane. Before the adsorbent materialreaches the end of its capacity to adsorb water vapor it is switchedfrom an adsorption step to a regeneration step. Regeneration can beaccomplished by raising the temperature of the adsorbent (TSA), purgingthe adsorbent with a dry stream (PPSA), reducing the pressure of theadsorbent (PSA) or by combinations of these methods. Once the adsorbenthas been regenerated it is ready for another adsorption cycle. If a PSAstep was used in the regeneration it has to be repressurized before itcan be used in the next adsorption cycle.

Because natural gas produced from subsurface regions is typicallysaturated with water (H₂O), dehydration is used to remove water toeither pipeline specifications (e.g., in a range between 4 pounds permillion cubic feet and 7 pounds per million cubic feet), NGLspecifications (e.g., in a range between 0.1 parts per million (ppm) and3 ppm), or LNG specifications (e.g., less than 0.1 ppm). Accordingly,typical methods and system utilize glycol dehydration along with anaddition mole sieve dehydration system to remove water from a producedstream to provide a gaseous stream that satisfies specifications. Thepipeline specifications may limit the water content to be less thanabout 4 pounds per million cubic feet to about 7 pounds per millioncubic feet or the dew point has to be less than −5° F. to −15° F.

Similarly, for cryogenic processing conventional molecular sieveadsorbent beds are used to rigorous dehydrate the gas after glycoldehydration. The rigorous dehydration reduces water concentrations toless than 0.1 part per million (ppm) in a slow cycle TSA or PTSAprocess. The molecular sieve adsorbent beds are large because they areonly regenerated once every hour to once a day. As such, the flow ofregeneration gas out of the molecular sieve adsorbent bed is not steadyand occurs in pulses when the molecular sieve adsorbent beds areregenerated. Further, the footprint of the slowly cycled molecular sieveadsorbent beds is large and the beds are heavy. The molecular sieveadsorbent beds typically use adsorbents, such as zeolite 5A and silicagel, which are prone to fouling. Moreover, adsorbent material in themolecular sieve adsorbent beds is configured as millimeter sized pelletsthat have mass transfer rate limitations in dehydration processes.

For example, U.S. Pat. No. 8,476,180 describes a process forregenerating a molecular sieve absorbent bed used for dehydrating anorganic solvent. The process describes using the molecular sieveadsorbent bed for dehydrating ethanol, which includes a dehydratingcycle where an ethanol and water vapor mixture is loaded onto themolecular sieve adsorbent bed at a first temperature to absorb water andrecover a substantially dehydrated ethanol vapor effluent. In aregeneration cycle, the molecular sieve adsorbent bed is subjected to atemperature swing technique whereby a dried gas, such as dried CO₂,heated to a second temperature greater than the first temperature, ispassed over the molecular sieve adsorbent bed. Water and residualethanol are removed with the CO₂ effluent and can be condensed andcombined with a feed input for a subsequent dehydrating cycle.Unfortunately, this configuration relies upon the large slowly cycledheavy molecular sieve absorbent beds to handle the separation. Further,because of the long periods of time required to heat and regenerate suchmolecular sieve adsorbent beds, the molecular sieve units typically havea large footprint and are heavy.

As another example, Intl. Patent Application Publication No.WO2010/024643 describes a multi-tube type ethanol dehydration devicethat uses a pressure swing adsorption process in which producingdehydrated ethanol and regenerating an absorbent material arealternately performed in one multi-tube type bed. The dehydration devicetransfers heat by using a heat source generated during the absorptionstep. Again, the dehydration device as described uses long cycle timesand has a larger footprint and are heavy.

As yet another example, U.S. Pat. No. 4,424,144 describes a method forshaping products of a 3A zeolite that are formed as beads or extrudateswithout any binder remaining. In this method, a 4A zeolite powder ismixed with a caustic solution and a metakaolin clay binder to formbeads. Then, the beads are converted to a binderless 4A zeolite product,which is given a partial calcium exchange followed by a potassiumexchange to obtain the desired 3A zeolite binderless bead. The size ofthe bead limits the mass transfer rate and the productivity. As aresult, the rate at which feed is processed per unit of adsorbentmaterial is significantly high.

Further, in addition to disadvantageous of certain types ofconfigurations for dehydration, the intrinsic performance of theadsorbent material may be problematic. For example, in Lin et al., thefundamental adsorption kinetic data for water on single-layer 3A isgiven. The linear driving force coefficients are in the range between 3per hour (h) and 7.4e-3 /h (e.g., a range between 3/h and 7.4×10⁻³/h)for different partial pressures from 1.24 kPa and 3.1e-4 kPa (e.g., arange between 1.24 kPa and 3.1×10⁻⁴ kPa). See e.g., Lin et al., Kineticsof water vapor adsorption on single-layer molecular sieve 3A:experiments and modeling, IECR, 53, pp. 16015-16024 (2014). This processis slow as the kinetics are slow acting.

Further still, in Simo et al., a pilot scale adsorber apparatus wasdesigned and constructed to investigate water and ethanoladsorption/desorption kinetics on 3A zeolite pellet for the designpurposes of a fuel ethanol dehydration pressure swing adsorption (PSA)process. See, e.g., at Marian Simo, Siddharth Sivashanmugam, ChristopherJ. Brown, and Vladimir Hlavacek, Adsorption/Desorption of Water andEthanol on 3A Zeolite in Near-Adiabatic Fixed Bed, Ind. Eng. Chem. Res.,48 (20), pp. 9247-9260 (2009). The breakthrough curves were utilized tostudy the effects of column pressure, temperature, flow rate, pelletsize, and adsorbate concentration on the overall mass transferresistance. The reference describes that the macropore and microporediffusion mechanisms are the controlling diffusion mechanisms. Theadsorbent is in pellet form with mass transfer resistances and rates.

Further, other publications describe the use of zeolite 4A in rapidcycle dehydration. These methods typically involve air drying and arenot as fouling prone as treatment of natural gas streams. Indeed, manyof the potential foulants in natural gas streams have the potential todiffuse into zeolite 4A over long exposure times. An example of the useof zeolite 4A in rapid cycle air drying is described in Gorbach et al.See Andreas B. Gorbach, Matthias Stegmaier and Gerhart Eigneberger,Compact Pressure Swing Adsorption Processes—Impact and Potential ofNew-type adsorbent-polymer monoliths, Adsorption, 11, pp. 515-520(2005).

As another example, U.S. Pat. No. 4,769,053 describes a latent heatexchange media comprising a gas permeable matrix. The gas permeablematrix is formed of a sensible heat exchange material that is capable ofabsorbing sensible heat from a warm air stream and releasing theabsorbed sensible heat into a cool air stream as the air streams flowthrough the heat exchange media. A layer of a coating compositioncomprising a molecular sieve is applied to at least a portion of thesurface of the heat exchange material. The molecular sieve has poresthat adsorbs moisture from a humid air stream flowing through the heatexchange media, and releases the adsorbed moisture into a dry air streamflowing through the heat exchange media. However, the heat exchangemedia does not appear to be capable of adsorbing contaminants from therespective streams.

While conventional approaches do perform dehydration on certain streams,these system have certain deficiencies, such as fouling and are notcapable of handling rapid cycle processing of streams. Indeed,conventional systems, which may utilize adsorbent materials, such as 4Aor 5A zeolites, silica or alumina, perform slow cycle dehydrationprocesses. These processes involve equipment and units that have alarger footprint and/or weight more than rapid cycle processes.

Accordingly, there remains a need in the industry for apparatus,methods, and systems that provide enhancements in adsorbent materialsfor swing adsorption processes. Further, the present techniques provideadsorbent materials with enhanced kinetics for rapid cycle dehydrationconfigurations, and enhanced foulant resistance. Accordingly, thepresent techniques overcome the drawbacks of conventional adsorbentmaterials.

SUMMARY OF THE INVENTION

In one embodiment, the present techniques describe a process forremoving water from a gaseous feed stream. The process comprisingperforming a rapid cycle swing adsorption process by: a) performing anadsorption step, wherein the adsorption step comprises passing a gaseousfeed stream through an adsorbent bed unit having a substantiallyparallel channel contactor to separate water from the gaseous feedstream to form a product stream, wherein the substantially parallelchannel contactor comprises an adsorbent material being a zeolite 3Ahaving (i) a K to Al atomic ratio is in a range between 0.3 and 1.0; and(ii) a Si to Al atomic ratio is in a range between 1.0 and 1.2; b)interrupting the flow of the gaseous feed stream; c) performing aregeneration step, wherein the regeneration step comprises removing atleast a portion of the water from the substantially parallel channelcontactor; and d) repeating the steps a) to c) for at least oneadditional cycle.

In another embodiment, a cyclical rapid cycle swing adsorbent system forremoving water from a gaseous feed stream is described. The rapid cycleswing adsorbent system comprising one or more adsorbent bed units thateach comprise: a housing forming an interior region; a substantiallyparallel channel contactor disposed within the interior region of thehousing, wherein the substantially parallel channel contactor comprisesan adsorbent material being a zeolite 3A having (i) a K to Al atomicratio is in a range between 0.3 and 1.0; and (ii) a Si to Al atomicratio is in a range between 1.0 and 1.2; and a plurality of valvessecured to the housing, wherein each of the plurality of valves is inflow communication with a conduit and configured to control fluid flowalong a flow path extending from a location external to the housingthrough the conduit and to the substantially parallel channel contactorthrough the valve.

In yet another embodiment, a composition or substantially parallelchannel contactor is described. The composition or substantiallyparallel channel contactor may include an adsorbent material, whereinthe adsorbent material is a zeolite 3A having (i) a K to Al atomic ratiois in a range between 0.3 and 1.0; and (ii) a Si to Al atomic ratio isin a range between 1.0 and 1.2. Further, the zeolite 3A comprise verygood quality crystals or excellent quality crystals. Also, the adsorbentmaterial has the K to Al atomic ratio is in a range between 0.35 and0.98 or in a range between 0.4 and 0.8.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other advantages of the present disclosure may becomeapparent upon reviewing the following detailed description and drawingsof non-limiting examples of embodiments.

FIG. 1 is a flow diagram of a process for fabricating an adsorbentmaterial in accordance with an embodiment of the present techniques.

FIGS. 2A and 2B are exemplary SEM diagrams of an adsorbent material.

FIG. 3 is a diagram of the ballistic chromatography instrumentation.

FIG. 4 is a diagram of the water breakthrough on a 3A packed adsorbentbed.

FIG. 5 is a diagram of the water breakthrough unit.

FIGS. 6A, 6B and 6C are diagrams of water breakthrough results on a 3Azeolite at various concentrations.

FIG. 7 is an exemplary diagram of water breakthrough results on a 3Azeolite capillary column.

FIG. 8 is an exemplary diagram of water isotherms on 3A zeolite crystalover temperature and pressure ranges.

FIGS. 9A and 9B are exemplary SEM diagrams of distribution of particlesizes.

FIG. 10 is an exemplary diagram of the Al NMR spectrum.

FIG. 11 is an exemplary diagram of the XRD pattern that shows the samplehas lost crystallinity.

FIG. 12 is an exemplary diagram of an exemplary XRD spectra recordedwith Cu K radiation.

FIG. 13 is an exemplary diagram of water isotherms for differentsamples.

FIG. 14 is an exemplary diagram of the water breakthrough on a 3A packedadsorbent bed.

FIG. 15 is another exemplary diagram of the water breakthrough on a 3Apacked adsorbent bed.

FIG. 16 is another exemplary diagram of the CO₂ non-equilibrium isothermmeasurements for different zeolite 3A samples.

FIG. 17 is an exemplary diagram of frequency response curves for wateron 3A crystals and control experiments.

FIG. 18 is an exemplary diagram of a sensitivity analysis for frequencyresponse experiments on H₂O on 3A crystals.

FIGS. 19A and 19B are exemplary SEM diagrams of an adsorbent material.

FIG. 20 is an exemplary diagram of frequency response curves for wateron larger crystal size 3A with 48% K.

FIG. 21 is an exemplary diagram of frequency response curves for wateron larger crystal size 3A with 81% K.

FIG. 22 is a three-dimensional diagram of the swing adsorption systemwith six adsorbent bed units and interconnecting piping in accordancewith an embodiment of the present techniques.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise explained, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which this disclosure pertains. The singular terms“a,” “an,” and “the” include plural referents unless the context clearlyindicates otherwise. Similarly, the word “or” is intended to include“and” unless the context clearly indicates otherwise. The term“includes” means “comprises.” All patents and publications mentionedherein are incorporated by reference in their entirety, unless otherwiseindicated. In case of conflict as to the meaning of a term or phrase,the present specification, including explanations of terms, control.Directional terms, such as “upper,” “lower,” “top,” “bottom,” “front,”“back,” “vertical,” and “horizontal,” are used herein to express andclarify the relationship between various elements. It should beunderstood that such terms do not denote absolute orientation (e.g., a“vertical” component can become horizontal by rotating the device). Thematerials, methods, and examples recited herein are illustrative onlyand not intended to be limiting.

As used herein, “stream” refers to fluid (e.g., solids, liquid and/orgas) being conducted through various equipment. The equipment mayinclude conduits, vessels, manifolds, units or other suitable devices.

As used herein, volume percent is based on standard conditions. Thestandard conditions for a method may be normalized to the temperature of0° C. (e.g., 32° F.) and absolute pressure of 100 kilopascals (kPa) (1bar).

The present techniques relate to the enhancement of adsorbent materialsfor rapid cycle swing adsorption systems used to dehydrate feed streamsusing zeolite 3A. Zeolite 3A are an LTA (e.g., a Zeolite structure typedesignated by the international zeolite association) structure type witha silicon (Si) to Aluminum (Al) (e.g., Si/Al) in a range between 1.2 and1.0 (inclusive of 1.0) with ratio of Potassium (K) cations to Al (K/Al)in a range between 0.2 and 1.0 (inclusive of 1.0). When the K/Al ratiois less than 0.95, the majority (>50%) of the remaining cations areSodium (Na) (e.g., the non-potassium cations). As such, there is a widerange of cation compositions that fall into the broad definition ofzeolite 3A. Accordingly, the present techniques may include a preferredrange of compositions and zeolite crystal quality for fouling tolerantrapid cycle rigorous dehydration swing adsorption processes. By way ofexample, one particular type of gas separation technology is swingadsorption, such as rapid temperature swing adsorption (RTSA), rapidcycle pressure absorption (RCPSA), rapid cycle partial pressure swingadsorption (RCPPSA), and not limited to but also combinations of theafore mentioned processes.

Swing adsorption processes may be used to remove water vapor from a gasmixture because water selectively adsorbs into the micropore of theadsorbent material, and may fill the micropores in certain situations.The swing adsorption processes (e.g., PSA and TSA) may be used toseparate gases of a gas mixture because different gases tend to fill themicropore of the adsorbent material to different extents. For example,if a gas mixture, such as natural gas, is passed under pressure througha vessel, such as an adsorbent bed unit, containing an adsorbentmaterial that is more selective towards water vapor than it is formethane, at least a portion of the water vapor is selectively adsorbedby the adsorbent material, and the gas exiting the vessel is enriched inmethane. With highly selective adsorbent materials having a sufficientlystrong isotherm, it is possible to rigorously dehydrate a methane ornatural gas stream. Rigorous dehydration is the removal of water so thatthe concentration of water in the product gas or stream (e.g., the gasexiting the adsorbent bed, such as a substantially parallel channelcontactor, during the adsorption step) is less than 50 ppm on a molebasis, preferably less than 1 ppm on a mole basis or even morepreferably less than 0.1 ppm on a mole basis.

In performing rapid cycle swing adsorption system, the adsorbent bed(e.g., a substantially parallel channel contactor) is regenerated beforethe adsorbent material reaches the end of its capacity to adsorb watervapor. PSA processes can be used to regenerate the adsorbent used fordehydration, but sufficient regeneration involves low pressures (e.g.,vacuum pressures) and long periods of time for regeneration. For rapidcycle dehydration processes, the adsorbent bed may be regenerated usingrapid cycle PSA, rapid cycle TSA and/or rapid cycle PPSA processes.After regeneration, the adsorbent material is then purged andrepressurized. For certain configurations, where methane comprises thefeed to the separation process, it is often beneficial to use a purgegas comprising at least 40% methane by volume. Then, the adsorbentmaterial is prepared for another adsorption cycle.

In rapid cycle processes the residence time of the gas contacting theadsorbent material in the adsorbent bed during the adsorption step istypically short. For rapid cycle swing adsorption processes, theresidence time for gas contacting the adsorbent material in theadsorbent bed during the adsorption step is less than 2.5 seconds,preferably less than 0.5 seconds and even more preferably less than 0.1seconds. Accordingly, the water removal adsorbent material has toequilibrate with the local gas environment in a time period that is lessthan one half of the gas residence time and more preferably less thanone fifth of the gas residence time and even more preferably less thanone tenth of the gas residence time.

Residence time is defined as the length of the adsorbent bed divided bythe average velocity of the feed stream passing through the adsorbentbed during the adsorption step of the swing adsorption process. It isdefined at the temperature and pressure of the feed stream passingthrough the adsorbent bed during the adsorption step. For water removal,the adsorbent material has to equilibrate with the local gas environmentin a time frame that is less than one half of the gas residence time andmore preferably less than one fifth of the gas residence time and evenmore preferably less than one tenth of the gas residence time.Equilibration is defined as the time it takes to load the zeolite of atleast half of the swing capacity of the adsorbent. For example, if azeolite 3A adsorbent is initially loaded with 5 millimole per gram (g)of water and the local concentration of water at the surface of thecrystal ultimately produces a loading of 12 millimole/g, or the swingcapacity is 7 millimole/g. The swing capacity for water vapor may bedefined at each location (point) within the adsorbent bed. Amanifestation of sufficiently fast kinetics is that the water vaporconcentration exiting the adsorbent bed does not rise during theadsorption step until an adsorption front passes through the adsorbentbed and a sharp breakthrough is observed. The swing capacity in theadsorbent bed at the initial breakthrough is at least one-third of theultimate swing capacity, which can be defined as the loading of theadsorbent bed after it has equilibrated with the feed minus the initialloading of the adsorbent bed. More preferably, the swing capacity in theadsorbent bed at the initial breakthrough may be at least three-fourthsof the ultimate swing capacity. Rapid cycle dehydration swing adsorptionprocesses of the present techniques are performed so that the adsorptionfront does not break through the adsorbent bed during the adsorptionstep and the front is contained in the adsorbent bed. To preventbreakthrough of a water front in a rapid cycle swing adsorptiondehydration processes, the adsorbent material has to equilibrate withthe water vapor flowing through the adsorbent bed in a time frame ofless than 0.5 seconds, preferably less than 0.1 seconds and even morepreferably in a time frame of less than 0.025 seconds.

Dehydration is utilized in cryogenic natural gas processing becausenatural gas contains significant amount of water vapor, which condensesand forms solid ice-like crystals (e.g., hydrates) as temperature andpressure change in cryogenic processing facilities. The crystalsbuild-up and foul processing equipment, such as heat exchangers. Toprevent this fouling, the gas fed to the cryogenic processing facilityhas to be dehydrated to levels below parts per million (ppm) waterlevels. In pipeline operations, the gas stream has to be dehydrated to aspecific dew point to produce pipeline quality product. The presenttechniques provide an adsorbent material composition that providesenhancements to dehydrating natural and associated gas using rapid cycleswing adsorption processes. The present techniques may be applicable toLiquefied Natural Gas (LNG) projects as well as Natural Gas Liquids(NGL) plants. The present techniques describe a method to dehydratenatural gas that may lessen capital expenses, lessen weight, lessen thefootprint and lessen energy usage as compared to conventional systems.This may be particularly useful in floating facilities, subseaconfigurations along with NGL plants.

By way of example, conventional practices utilize large slow cyclemolecular sieve adsorbent beds that are thermally regenerated. Theadsorbent material used is typically zeolite 4A or 5A. In someapproaches, the adsorbent used is silica or alumina. Combination orlayers of adsorbent are used in many situations. By comparison, rapidcycle swing adsorption processes provide enhancements of using lessadsorbent, reducing size of equipment to have less capital cost and footprint. In addition, the rapid cycle swing adsorption processes makepossible a mobile system to be used in remote areas, offshore, and otherhard to reach places. The technology can also be better integrated intoNGL and LNG facilities than conventional slow cycle molecular sieveadsorbent beds that infrequently have regeneration gas.

Moreover, rapid cycle swing adsorption dehydration processes usingappropriately selected zeolite 3A can be performed at various gasprocessing facilities, such as a gas plant, an offshore platform, aswell as a wellhead on land or subsea for any dehydration processing. Theadvantages of rapid cycle dehydration processes using appropriatelyselected zeolite 3A are more effective for dehydration to below partsper million water levels in the feed gas to NGL or LNG plants thatutilize cryogenic processing. Because the rapid kinetic transport ofwater in the zeolite 3A adsorbent involves regeneration with a modestamount of purge, it is possible to develop fouling tolerant dehydrationprocesses that may be integrated into such facilities. By way ofexample, an adsorbent bed containing the zeolite 3A adsorbent may becapable of rigorous dehydration of high pressure natural gas streams(e.g., pressures greater than 300 psi, or more preferably greater than600 psi). The rapid cycle swing adsorption process relies upon thekinetic adsorption rate of water on zeolite 3A, which is very fast evenat various low water activities. Moreover, the rate of water adsorptionis not hindered by foulants and adsorbents have a high re-generablewater capacity (e.g., in excess of about 3 millimole per gram (mmol/g))even at low water concentrations of tens to hundreds of ppm in the feedstream. Testing shows that a wet stream can pass through an adsorbentbed of 3A with less than 0.1 s residence time in the bed to achieve thedesired water specifications of either pipeline or LNG. The adsorbentbed can then be taken off line and the water can be removed by eitherdepressurizing and flushing the bed with dry gas or flushing the bedwith hot gas with or without depressurization (e.g., performing a purgeor heating step). To enhance the efficiency of water removal, it ispreferred that the zeolite 3A adsorbent be a structured adsorbent bedthat forms a contactor, such as a substantially parallel channelcontactor. It is further preferred that the structured adsorbent bed beconfigured to operate in a parallel contacting mode so that a sharpadsorption front moves along the structured adsorbent during theadsorption or feed step. Specific zeolite 3A materials may be used toconstruct this contactor. In an alternative embodiment, the contactormay be fabricated with either zeolite 4A or 5A and ion exchanged tozeolite 3A after construction. Because the rapid kinetic transport ofwater in the 3A adsorbent, the adsorbent material may be regeneratedwith a modest amount of purge. The small effective pore size of thesuitable zeolite 3A materials makes it is possible to develop foulingtolerant rigorous dehydration processes that are well integrated intoNGL and LNG plants.

Zeolite 3A samples with fouling tolerance sufficient to be used in rapidcycle natural gas dehydration have a K cation content that on a molarbasis is greater than 30% of the Al content. It is preferred that atleast 90% of the remaining or non-potassium cations be Na. In a morepreferred embodiment the fouling tolerance is enhanced with a K cationcontent that on a molar basis is greater than 35% of the Al content. Inan even more preferred embodiment, fouling tolerance is further enhancedwith a K cation content that on a molar basis is greater than 50% of theAl content. Extremely fouling tolerant zeolite 3A materials have a Kcation content that on a molar basis is greater than 80% of the Alcontent. Two different methods may be used to assess the foulingtolerance of different zeolite 3A samples. The first method involvesdirect exposure to foulants and the measurement of how water transport(e.g., swing adsorption capacity and kinetics) are altered afterexposure. Example 5 illustrates this methodology and shows the foulingtolerance of high quality zeolite 3A samples with 40% K content. Asecond method provides an approach to assess the fouling tolerance ofdifferent zeolite 3A samples from the isotherm of CO₂ measured when thesample has equilibrated with CO₂ for a time of less than 3 minutes. Tohave sufficient fouling tolerance, it is preferred to have a CO₂capacity (25° C. and less than 3 minute equilibration times in isothermmeasurement) of less than 2 milli moles/gram at 760 torr. A morepreferred fouling tolerance is a CO₂ loading in an isotherm measurement(at 25° C. with less than 3 minute equilibration times) of less than 1.5millimole/gram at 760 torr. An even more preferred fouling tolerance isa CO₂ loading in an isotherm measurement (at 25° C. with less than 3minute equilibration times) of less than 0.5 millimole/gram at 760 torr.

To obtain rapid kinetics less than 10%, preferably less than 5% and evenmore preferably less 1% of the Al within the zeolite crystal should beextra framework aluminum. Extra framework aluminum blocks access ofwater into the micropore structure of zeolite 3A and can be measured inan aluminum Nuclear Magnetic Resonance (NMR) experiment. Ion exchangeprocedures that convert highly crystalline zeolite 4A into zeolite 3Acan in many instances degrade the zeolite framework and yield extraframework aluminum. Example 6 shows how an ion exchange procedure usinga buffer produced this type of degradation.

To obtain rapid kinetics, the zeolite 3A sample should be highlycrystalline. X-ray diffraction can be used to assess the crystallinityof a zeolite sample. Amorphous material in the sample is shown by broaddiffuse peak in the x-ray diffraction pattern. When the x-raydiffraction pattern is recorded using copper-potassium (Cu K) x-rayradiation a broad peak from amorphous material in the sample appears asa maximum at a two-theta of approximately 28 degree. Subtracting thebaseline in the diffraction pattern provides a measure of the amplitudeof this amorphous peak. The ratio of this amorphous peak amplitude tothe strong sharp peak from zeolite 3A at a two-theta of about 24 degreesprovides a measure of the amount of amorphous material in the sample. Itis preferred that this ratio is less than 0.2, more preferably less than0.1 and even more preferably less than 0.05. Another measure comparesthe amplitude of the amorphous peak to the peak a two-theta of 30degrees. Further, the ratio may be preferred to be less than 0.2, morepreferably less than 0.1 and even more preferably less than 0.05.Examples 6 and 8 show the ability of x-ray diffraction to detectamorphous materials in zeolite 3A samples.

To obtain rapid kinetics fouling tolerance and high working capacitiesin rapid cycle swing adsorption dehydration process, it is preferred touse a zeolite 3A with a K/Al atomic ratio between 0.3 and 1.0,preferably between 0.4 and 0.98, preferably between 0.35 and 0.98 andeven more preferably between 0.4 and 0.8. It is preferred that more than50% of the reaming cations in the zeolite 3A are Na, more preferablymore than 80% and even more preferably more than 90%.

To obtain fast kinetic and rapid equilibration, it is preferred that themass average zeolite crystal size be less than 20 microns, morepreferable less than 10 microns, less than 5 microns and even morepreferable less than 3 microns. Similarly the average size of zeoliteaggregates should be less than 40 microns, more preferably less than 20microns and even more preferably less than 10 microns.

Kinetics of zeolite samples can be measured in the laboratory usingballistic chromatography. For quantification of fast diffusivitymeasurements, a variation of the chromatographic breakthrough techniquemay be utilized. The technique has been described in U.S. PatentPublication No. 2016/0175759 in the context of CO₂ adsorption. In thesemeasurements, a small amount of sample (e.g., zeolite crystals) isplaced in a packed bed of about 1 centimeter (cm) in lengths, and about0.1 cm in diameter. The weight of the dry sample in the packed bed isaccurately measured and depending on how the packed bed is loaded canrange between 2 milligrams (mg) and 20 mg. The sample placed into thepacked bed is composed of individual zeolite crystals or smallaggregates of the crystals. For water vapor delivery helium gas streamis passed through a bubbler, which is maintained at a temperature lowerthan the temperature of the adsorption bed to avoid condensation. A massspectrometer with a fast data acquisition is used to monitor theeffluent concentration of water vapors.

The gas residence time in such a system can be calculated based onequation (el):

t _(res) =L/v   (e1)

where L is the adsorption bed length, and v is the gas velocity. Also,the gas velocity is calculated based on equation (e2):

$\begin{matrix}{v = {\frac{F_{0}}{ɛ\; S}\left( \frac{P_{0}}{P} \right)\mspace{11mu} \left( \frac{T}{T_{0}} \right)}} & \left( {e\; 2} \right)\end{matrix}$

where F₀ is the volumetric flow rate at standard temperature T₀ andpressure P₀, S is the bed cross-sectional area, and ε is the bedporosity (fraction of void space between zeolite crystals).

In the developed system, the gas is flowed into the bed at a flow rateof about 10 standard cubic centimeters (cc) per minute. Pressure dropthrough the bed may be in a range between about 5 to about 50 psidepending on the size of the crystals, the amount of sample and how theyare packed into the bed. When there is a pressure drop through the bed,the pressure used to calculate the residence time is the average of theinlet and the outlet pressure. Typically, the gas velocity is on theorder of about 30 centimeters per second (cm/s), and the correspondinggas residence time is very short, on the order of t_(res)=0.03 seconds(s). The response of the column is indicative of the equilibrium andkinetics of the adsorption process.

If the kinetics of the sample are fast, a sharp breakthrough frontappears at a time that is more than 30 seconds later than the time atwhich a front appears with no sample in the cell. The swing adsorptioncapacity of the sample at the point of breakthrough can be calculatedfrom the time of breakthrough and can be directly calculated from therate at which molecules are being fed into the bed. It is preferred thatthis swing capacity at the initial breakthrough is at least one-third ofthe ultimate swing capacity which can be defined as the ultimate loadingof the bed calculated from the shape of the breakthrough curve and therate at which molecules are delivered. More preferably, the swingcapacity in the bed at the initial breakthrough may be at leastthree-fourths of the ultimate swing capacity. The ultimate swingadsorption capacity can be calculated from the time average t[averaged]of the instantaneous concentration at the outlet c and the outletconcentration at long times co, as shown by equation (e3):

t[averaged]=∫₀ ^(∞)(1−c/c ₀)dt   (eq3)

where t=0 is taken to be the time at which a front appears with nosample in the cell. The ultimate swing adsorption of the columnn[ultimate] is calculated from equation (e4):

$\begin{matrix}{{n\lbrack{ultimate}\rbrack} = \frac{F_{0}{t({averaged}\rbrack}c_{0}}{m}} & \left( {e\; 4} \right)\end{matrix}$

where the swing adsorption rate the time (t[breakthrough) the sharpbreakthrough front breaks through the column is

$\begin{matrix}{{n\lbrack{breakthrough}\rbrack} = \frac{F_{0}{t\lbrack{breakthrough}\rbrack}c_{0}}{m}} & \left( {e\; 5} \right)\end{matrix}$

where samples with n[breakthrough]/n[ultimate]>1/3 have an initialbreakthrough capacity greater than one-third of the ultimate swingcapacity. Such samples are then candidates for qualifying as having fastkinetics.

These samples equilibrate with water vapor in a time frame that is lessthan one third of the gas residence time (t_(res)). As such, theballistic chromatography method measures the time frame it takes watervapor to equilibrate with a zeolite 3A sample. It is preferred that thistime frame is less than 0.5 seconds, preferably less than 0.1 secondsand even more preferably in a time frame of less than 0.025 seconds.When kinetic are slow, water breaks through the bed at time almost equalto a blank bed or the water baseline concentration rises noticeablybefore the breakthrough occurs. Similarly, the breakthrough capacity forsamples with such slow kinetics are small. For zeolite 3A materials usedin rapid cycle swing adsorption processes with a residence time for gascontacting the adsorbent material in the adsorbent bed during theadsorption step of less than 2.5 seconds, the time it takes water vaporto equilibrate with the zeolite 3A material should be less than 0.5seconds. For Zeolite 3A materials used rapid cycle swing adsorptionprocesses with a residence time for gas contacting the adsorbentmaterial in the adsorbent bed during the adsorption step of less than0.5 seconds, the time it takes water vapor to equilibrate with thezeolite 3A material should be less than 0.1 seconds.

Another parameter that may be used to describe the breakthrough when thegas residence time is less than 2.5 seconds more preferably less than0.5 seconds and even more preferably less than 0.1 seconds is aparameter theta θ that can be estimated from the slope of the midpointslope of the breakthrough response c/c₀, as shown by equation (e6):

θ=t[res]*Slope*1000   (e6)

where t[res] is the residence time of gas in the column, and Slope isthe slope of the breakthrough curve c/c₀ between c/c₀=0.4 and c/c₀=0.6.For a fast kinetic processes, it is preferred that this parameter theta(θ) is greater than at least 0.2, or more preferentially greater than0.5, and even more preferred greater than 2. For zeolite 3A materialsused in rapid cycle swing adsorption processes with a residence time forgas contacting the adsorbent material in the adsorbent bed during theadsorption step of less than 2.5 seconds, the parameter theta (θ) shouldbe greater than 0.2. For zeolite 3A materials used rapid cycle swingadsorption processes with a residence time for gas contacting theadsorbent material in the adsorbent bed during the adsorption step ofless than 0.5 seconds, the parameter (θ) should be greater than 0.5.

Substantially parallel channel contactors with mass transfercharacteristics closely resembling those of the zeolite 3A adsorbent canbe constructed by coating thin layers of zeolite 3A and a binder onto amonolith. Substantially parallel channel contactors, such as monoliths,provide very low pressure drop as compared to conventional pellet orother packed beds, which provides a mechanism for the economic use ofsignificantly higher gas velocities and hence higher productivity. Oneof the primary factors to the performance of a substantially parallelchannel contactor and its application for rapid cycle swing adsorptionsystems is to avoid or minimize mass transfer resistances, and thusallow the intrinsic speed of the primary adsorber, typically a molecularsieve, such as zeolite 3A, to be realized. Avoidance of mass transferresistances in rapid cycle contactors provide the conditions tofacilitate the generation of sharp adsorption fronts, particularly forstrong Type 1 isotherm adsorption systems, such as water, in 3A zeolite.Sharp fronts within the length of the adsorption contactor provideefficient adsorbate removal to very low concentrations.

Minimization of mass transfer resistance may be accomplished in asubstantially parallel channel contactor by several steps. Gas filmtransfer resistance is minimized by making the gas channels in thecontactor of small diameter, such that the distance any adsorbatespecies has to diffuse in the gas phase is limited to one half thediameter of the gas channel. Gas channel diameters, or heights, of lessthan 2 millimeter are preferred, less than 1 millimeter are morepreferred, and less than 600 microns are most preferred. Secondly,limiting the thickness of adsorbate containing coatings reduces thedistance that adsorbate species has to diffuse through the macroporesand mesopores of the composited adsorbate coating. Preferably, thevolume of the zeolite 3A or other molecular sieve is greater than thatof the binder and thickness of the layer is less than 800 microns,preferably less than 200 microns and even more preferably less than 125microns, most preferably less than 60 microns. Further, it is beneficialto minimize the amount of mesopores within the coating layer, with apredominance of macropores being preferred due to the faster diffusionspeeds of gas species in macropores as compared to mesopores. It ispreferred that at least 50% of the pore volume of the adsorbate coatinglayer is in macropores, i.e. pore diameters greater than 50 nanometers,more preferably at least 75%, and most preferably greater than 90%.Lastly, adsorbent coating layers with low intrinsic tortuosity arepreferred.

While not limiting, suitable contactors may be constructed of adsorbatecoatings on ceramic monoliths, or spaced laminated support sheets ofmetal, metal mesh, polymer, or polymer mesh, or various screens whenlaminated and spaced with spacers or other means to provide a gas flowchannel parallel to the coating layers. Corrugated metal sheets, eitherlayered or spiral wound coated with an adsorbent layer are particularlyuseful and flexible in their possible designs and gas channelcharacteristics. Contactors constructed from multiple monoliths or othersuch structures stacked in series are also particularly useful, asspaces between the monoliths or such provide gas mixing and can minimizefront dispersion caused by variations in adsorbate coating thicknessesor gas channel diameters.

Beneficially, the present techniques provide suitable adsorbentmaterials that may be utilized to enhance kinetics for rapid cycledehydration configurations, and to enhance foulant resistance (e.g.,resistance to fouling from molecules including various hydrocarbons,amines, and alcohols). Further, the present techniques may be used tolessen the footprint of the contaminant removal system. For example, themolecular sieve adsorbent beds may be five times greater than theadsorbent beds utilized in swing adsorption processes in certain similarconfigurations. In addition, the weight of the molecular sieve adsorbentbeds may be more than ten times greater than the adsorbent beds (e.g.,substantially parallel channel contactor) utilized in swing adsorptionprocesses. Further, the molecular sieve adsorbent beds typically useadsorbents, such as zeolite 5A and silica gel, which are prone tofouling. Adsorbent materials in the adsorbent bed is configured asmillimeter sized pellets that have mass transfer limitations indehydration processes, while the present techniques overcome the masstransfer and fouling limitations by utilizing specific adsorbentmaterials, such as certain zeolite 3A in a structured adsorbent.

In one configuration, a process for removing water from a gaseous feedstream. The process comprises performing a rapid cycle swing adsorptionprocess by: a) performing an adsorption step, wherein the adsorptionstep comprises passing a gaseous feed stream through an adsorbent bedunit having a substantially parallel channel contactor to separate waterfrom the gaseous feed stream to form a product stream, wherein thesubstantially parallel channel contactor comprises an adsorbent materialbeing a zeolite 3A having (i) a K to Al atomic ratio is in a rangebetween 0.3 and 1.0; and (ii) a Si to Al atomic ratio is in a rangebetween 1.0 and 1.2; b) interrupting the flow of the gaseous feedstream; c) performing a regeneration step, wherein the regeneration stepcomprises removing at least a portion of the water from thesubstantially parallel channel contactor; and d) repeating the steps a)to c) for at least one additional cycle.

As further enhancements, the process may include some additionalvariations to the process. For example, the rapid cycle swing adsorptionprocess may comprise a rapid cycle pressure swing adsorption process, arapid cycle temperature swing adsorption process, a rapid cycle partialpressure swing adsorption process, or any combination thereof; theregeneration step may further comprise performing a purge step, whereinthe purge step comprises passing a purge stream into the adsorbent bedunit to remove the at least a portion of the water from thesubstantially parallel channel contactor to form a purge product stream;the rapid cycle swing adsorption process may comprise a rapid cyclepressure swing adsorption process; may include performing one or moredepressurization steps after step b) and prior to step c), wherein thepressure within the adsorbent bed unit is reduced by a predeterminedamount with each successive depressurization step; may include heatingthe substantially parallel channel contactor to promote the removal ofthe at least a portion of the water from the substantially parallelchannel contactor to form a purge product stream; and may includepassing a heated purge stream through the substantially parallel channelcontactor to promote the removal of the at least a portion of the waterfrom the substantially parallel channel contactor to form a purgeproduct stream; the feed pressure is in the range between 400 pounds persquare inch absolute (psia) and 1500 psia; wherein the gaseous feedstream may comprise hydrocarbons and H₂O, wherein the H₂O is in therange of two parts per million volume to saturation levels in thegaseous feed stream; wherein the gaseous feed stream may be ahydrocarbon containing stream having greater than one volume percenthydrocarbons based on the total volume of the feed stream; wherein thecycle duration is greater than 2 seconds and less than 300 seconds;wherein residence time for gas in the gaseous feed stream contacting theadsorbent material in the substantially parallel channel contactorduring the adsorption step is less than 2.5 seconds, is less than 0.5seconds or is less than 0.1 seconds; and/or wherein the concentration ofwater in the product stream is less than 50 parts per million on a molebasis, is less than 1 parts per million on a mole basis or is less than0.1 parts per million on a mole basis.

As additional enhancements, the substantially parallel channel contactormay include certain variations. For example, the adsorbent material mayhave the K to Al atomic ratio is in a range between 0.35 and 0.98 or ina range between 0.4 and 0.8; the adsorbent material may have greaterthan 50% of the non-potassium cations in the zeolite 3A being Na,greater than 80% of the non-potassium cations in the zeolite 3A beingNa, or greater than 90% of the non-potassium cations in the zeolite 3Abeing Na; wherein the adsorbent material may have a fouling tolerant,wherein fouling tolerant is defined as the adsorbent material having aCO₂ capacity at 25° C. and less than 3 minute equilibration times inisotherm measurement of less than 2 milli moles/gram at 760 torr orfouling tolerant is defined as the adsorbent material having a CO₂capacity at 25° C. and less than 3 minute equilibration times inisotherm measurement of less than 0.5 milli moles/gram at 760 torr;wherein average size of zeolite aggregates in the zeolite 3A may be lessthan 40 microns or less than 10 microns; wherein mass average size ofzeolite aggregates in the zeolite 3A may be less than 5 microns; whereinthe purge stream may be predominately methane and/or wherein the zeolite3A comprise very good quality crystals or excellent quality crystals.The present techniques may be further understood with reference to theFIGS. 1 to 22 below.

FIG. 1 is a flow diagram 100 of a process for fabricating an adsorbentmaterial in accordance with an embodiment of the present techniques. Inthis diagram 100, the method involves determining an adsorbent materialand using that adsorbent material in a swing adsorption process, such asa rapid cycle swing adsorption process. In particular, the method mayinclude determining a configuration for the adsorbent material, as shownin block 102, producing the adsorbent material, as shown in blocks 104and 106, and utilizing the adsorbent material in a swing adsorptionprocess, as shown in block 108.

The method begins at block 102. In block 102, a configuration for anadsorbent material is determined. This determination may involvemodeling and identifying various aspects of the configuration, such asdetermining the mechanical features of the configuration, determiningflow paths through the configuration, determining the cell size,determining the pressure drop, determining the operating conditions thatthe configuration is subject to (e.g., pressures, temperatures andstream compositions), determining the contaminants to be adsorbed by theadsorbent material in the configuration; and/or entrance and exit valveconfiguration to control the various flows and/or velocities, and henceresidence times during the process must also be determined.

Once the adsorbent material is determined, the adsorbent material isproduced, as shown in blocks 104 and 106. At block 104, the adsorbentmaterial is created. The creation of the adsorbent material may involvemixing an active adsorbent material with organic and/or inorganicbinders to provide a specific formulation that provides good adhesion ifused as a coating, or good structural stability if used as aself-supported monolith. At block 106, the created adsorbent materialmay be verified. The verification of the created adsorbent material mayinclude using sensors to obtain measurements on the created adsorbentmaterial to identify voids, fractures and/or non-homogeneous sections ofthe created adsorbent material.

Once produced, the adsorbent material may be utilized in a swingadsorption process, as shown in block 108. For example, the adsorbentmaterial may be used in a rapid cycle swing adsorption process to removeone of more contaminants from a feed stream. Exemplary swing adsorptionprocesses are described in U.S. Patent Application Publication Nos.20170056810; 20170056813; 20170056814 and 20170056815, which are eachherein incorporated by reference in their entirety.

In certain embodiment, a rapid cycle dehydration process may utilizespecific zeolite 3A to enhance the process compared to conventionalglycol dehydration and molecular sieve dehydration processes, whichtypically involve long time cycles. This rapid cycle utilizes the fastwater kinetics on specific zeolite 3A in addition its high watercapacity and enhanced fouling resistance. Accordingly, a wet stream maypass through an adsorption bed of specific zeolite 3A with less than 0.1second residence time in the adsorbent bed to achieve the desired waterspecifications for a pipeline or a LNG system. The adsorbent bed canthen have the adsorption step interrupted and a regeneration step may beperformed to remove water through one or more depressurization stepsand/or purge steps, which may involve a dry gas stream isothermally orwith added heat.

In contrast to other proposed usage of zeolite 3A, the conventionalusage of zeolite 3A is forming them as pellets instead of thin layers orstructures used in a rapid cycle contactor. Conventional zeoliteadsorbent materials are made by compressing or extruding zeolitecrystals (e.g., about 1 micrometer (μm) in diameter) into pellets (e.g.,a few millimeters in diameter) with the aid of a binder. The masstransfer in pellets may be controlled by macropore diffusion resistancesin addition to mass transfer in zeolite crystals, also called microporediffusion. Macropores (e.g., voids in the pellet) act as a conduit totransport the gas molecules from the pellet surface to the particleinterior. A combination of two diffusion mechanisms, Knudsen diffusionand the molecular (bulk) diffusion, is possible in the macropore regiondepending on the size of the pore, the pressure, and the diffusingmolecule. Once the macropore diffusion in the pellet is slower than themicropore diffusion in zeolite crystals, the rate dominating step isdetermined by the mass transfer in the macropores. This is often thecase with the use of conventional pelletized adsorbent systems.

Example 1 is an example that provides evidence of fast kinetics for agood commercial sample of zeolite 3A crystals. The commercial 3A sampleshave a Si/Al ratio of about 1. Approximately 40 mole % of the cations inthese samples were potassium (K) with the balance being Na. X-raydiffraction studies show that this was highly crystalline material withno detectable extra framework Al by NMR. The sample is highlycrystalline, as shown by the flat baseline of the x-ray diffractionpattern in response 1206 in FIG. 12, which is discussed further below.Herein the magnitude of the amorphous alumina hump is defined as theelevation of the baseline measured near 28 degrees two-theta, whenmeasured above a baseline drawn between about 20 degrees two-theta and40 degrees two-theta in the x-ray diffraction pattern. The ratio of theamplitude of hump to the strong sharp peak at a two-theta of near 30 isalmost zero, satisfying the most preferred ratio of less than 0.05 tohave good crystallinity. Similarly, the comparison with the x-raydiffraction peak from zeolite 3A at a two-theta of 24 degrees is almostzero, satisfying the most preferred ratio of less than 0.05 to have goodcrystallinity.

FIGS. 2A and 2B are exemplary SEM diagrams 200 and 220 of distributionof particle sizes for the commercial zeolite 3A, while FIGS. 9A and 9Bare additional exemplary SEM diagrams 900 and 920 of distribution ofparticle sizes for the commercial zeolite 3A. There was a wide range ofparticle sizes in the sample with the bulk of the particles in a rangefrom 1 to 3 microns. As such, the zeolite particle size is in the mostpreferred range for fast kinetics.

FIG. 3 is a diagram 300 of the ballistic chromatography instrumentation,which is used in the present example. In this diagram 300, two Helium(He) gas cylinders, such as He gas cylinder 302 and 306, provide astream to respective mass flow meters, such as mass flow meters 304 and308. One stream is passed through a bubbler 310 before passing to a gaschromatograph (GC) oven 312, while the other stream passes directly intothe GC oven 312. In the GC oven 312, the streams are passed through avalve 314 and then through the sample bed 316 to another valve 318 thatprovides the stream to an outlet or to a mass spectrometer 319.

In this instrumentation, the basic underlying principle of ballisticchromatography is the measurement of the adsorption and desorption of agaseous adsorbate that is switched (e.g., valved) onto and off of asolid sample in an ultra-short (e.g., about 1 centimeter (cm) long),packed sample bed 316. The small bed size models a short bed residencetime (e.g., 10's to 100's of milliseconds) of the sorbate gas, thusdecreasing dispersion effects that can convolute the breakthrough curve.Water is introduced through using of a bubbler 310 to saturate thehelium stream from the He gas cylinder 302. The concentration of waterin the saturated helium stream is dependent on both the temperature andpressure inside the bubbler 310. The exact concentration of water iscalculated for every run or test. Typical values are around 1% (mol/mol)water in helium. The flow rate is about 10 standard cubic centimetersper minute (sccm). Outlet pressure is open to atmosphere, and inletpressure is in the range from about 0.5 bar to 3 bar higher than outletpressure. The pressure drop through the small packed bed 316 is relatedto a function of bed packing.

To manage the flow of fluids, various equipment may be used within thesystem. For example, various valves may be disposed along theconnections between equipment. These valves may include butterfly valveor plug valve, for example. As a specific example, a valve 320 may bedisposed between the He gas cylinder 302 and the mass flow meter 304,while valve 322 may be disposed between the bubbler 310 and the GC oven312 and valve 324 may be disposed between the He gas cylinder 306 andthe mass flow meter 308. Each of these valves 320, 322 and 324 may beconfigured to independently block passage of the fluid flow or permitfluid flow based on the setting of the respective valve. In addition,other valves may be used to pass the streams from the GC oven 312 toother equipment or for venting. For example, a needle valve 326 may bein fluid communication with the GC oven 312 and configured to vent thestream from the valve 314, while the needle valve 328 may be in fluidcommunication with the GC oven 312 and configured to vent the streamfrom the valve 318. These various valves may manage the flow within thesystem.

In addition, various monitors or gauges, such as temperature and/orpressure gauges, may be used within the system to measure conditions ofthe streams at various locations within the system. For example, a firstpressure gauge 330 may be disposed between the mass flow meter 304 andthe bubbler 310 to monitor the pressure or changes in stream at thislocation, while a second pressure gauge 332 may be disposed between themass flow meter 308 and the valve 314 to monitor the pressure or changesin stream at this location and a third pressure gauge 334 may bedisposed between the valve 318 and the outlet, or the needle valve 328,to monitor the pressure or changes in stream at this location. Each ofthese gauges may be communicate with a control unit (not shown) tomanage the operation of the system.

To establish the intrinsic kinetics of zeolite 3A using ballisticchromatography, small (e.g., 3 milligram (mg) to 10 mg) packed adsorbentbed of zeolite crystals were used to measure breakthrough in a shortresidence time. FIG. 4 is a diagram 400 of the water breakthrough on a3A packed adsorbent bed. In this diagram 400, a first response 406 and asecond response 408 are shown along a time after water exposure axis 402in minutes and a relative abundance axis 404. In this diagram 400, thebreakthrough curves of 3A samples at water concentration of 3 percent(%) in a packed bed configuration along with the associated blankconfiguration. The first response 406 is for an empty bed, while thesecond response 408 is for 3A packed bed. The data is relatively flatbefore the breakthrough front, with no initial bleed through of water.Thus, the uptake of water is faster than the residence time of the waterin the sample beds. To achieve this type of performance, the sample hasto equilibrate with the flow gas stream in a time that is at least fivetimes shorter than the residence time of gas through the sample bed. Inthe example, the residence time is 31 milliseconds through the packedbed. Because there was a sharp breakthrough front in diagram 400 withgood swing adsorption capacity, the time to equilibrate water vapor withthe zeolite 3A sample was less than about one-third of the residencetime or less than 10 milliseconds. The blank response 406 is similar tothe 3A packed bed response 408. The zeolite 3A adsorption frontbreakthrough time is measured from the time at which the blank breaksthrough. To calculate the fraction of the ultimate capacity atbreakthrough the concentration after breakthrough is adjusted by theresponse of the blank. Because the shape of the response curve for 3Azeolite in the bed after breakthrough is very similar to that of theblank, the adsorption capacity at breakthrough is more than 75% of theultimate swing adsorption capacity. As such, the kinetics of the sampleare nearly in the most preferred range. Accordingly, the slope of thebreakthroughs for the 3A zeolite samples is indicative of the adsorptionkinetics. The theta parameter as defined above is equal to 3.66, and theratio for theta is in the most preferred range. The estimated capacityfrom the breakthrough is about 17.5 weight percent (wt%) thiscorresponds to a swing adsorption capacity at breakthrough of 9.8millimole/gram.

Example 2 is an example that provides evidence of fast kinetics for thecommercial zeolite 3A crystals studied in Example 1 with a differentballistic breakthrough unit.

To measure the water breakthrough at different concentrations, anindependent water breakthrough unit may be utilized, which is shown inFIG. 5. The advantage of this water breakthrough unit compared to theunit in Example 1 is to provide a wide range of feed concentrationsinstead of using a single concentration condition by utilizing adilution stream. FIG. 5 is an exemplary diagram 500 of a waterbreakthrough unit. In this diagram 500, various He sources are providedvia mass flow controllers (MFCs), such as MFC 502, 504 and 506. Each ofthe streams from the MFC 502, 504 and 506 is passed to the sample 510.One of the streams has a water sparger 508 in the flow path from the Hesource to the MFC 502. After passing through the sample 510, the streamis conducted away from the sample and may be passed to a pressurecontroller (PC) 512 and mass spectrometer (MS) 514 or to a conduit 518.Further, the sample may be disposed within an enclosure 519, which isconfigured to isolate sample 510 from external conditions and may beconfigured to adjust the conditions (e.g., pressure, temperature, etc.)that the sample 510 is exposed to within the enclosure 519.

To manage the operation of the unit, a control unit 516 manages and/orcontrols the operation of the various components in this system. As thissystem has flexibility of diluting water concentration by mixing gasesand adjusting temperature of water sparger 508, water concentration canbe adjusted to a desired level in addition to saturated waterconcentration. The control unit 516 may be configured to communicatewith the MFCs 502, 504 and 506, pressure controller (PC) 512 and massspectrometer (MS) 514, which may be via communication equipment or lines540.

To manage the flow of fluids, various equipment may be used. Forexample, various valves may be disposed along the connections betweenequipment. These valves may include butterfly valve or plug valve, forexample. As a specific example, a valve 520 may be disposed between theHe source (e.g., a He gas cylinder) and the water sparger 508, while avalve 522 may be disposed between the He source (e.g., a He gascylinder) and the MFC 504 and a valve 524 may be disposed between the Hesource (e.g., a He gas cylinder) and the MFC 506. Also, a valve 526 maybe disposed downstream of the PC 512. Each of these valves 520, 522, 524and 526 may be configured to independently block passage of the fluidflow or permit fluid flow based on the setting of the respective valve.In addition to valves, other equipment, such as blowers or compressors,may be used to conduct away the streams from the sample 510. Forexample, a first blower 530 may be in fluid communication with theconduit upstream of the MS 514 and configured to conduct away the streamfrom the sample 510, while a second blower 532 may be in fluidcommunication with the stream downstream of the MS 514 and configured toconduct away the stream from the MS 514. Also, a third blower 534 may bein fluid communication with the stream downstream of the PC 512 andconfigured to conduct away the stream from the PC 512. Accordingly, incertain configurations, these various valves and blowers may be used tomanage the flow within the system.

Results from the water breakthrough unit in FIG. 5 are shown in FIGS.6A, 6B and 6C. FIGS. 6A, 6B, 6C are diagrams 600, 620 and 640 of waterbreakthrough results on a 3A zeolite at various concentrations. FIG. 6Ais a diagram 600 of water at 10000 ppmv (1%) at 1 bar. In this diagram600, a first response 608 and a second response 606 are shown along atime axis 602 in minutes and a concentration axis 604 in parts permillion (ppm). The first response 608 is a blank, while the secondresponse 606 is a 3A. FIG. 6B is a diagram 620 of water at 1890 ppm at 1bar. In this diagram 620, a first response 628 and a second response 626are shown along a time axis 622 in minutes and a concentration axis 624in parts per million (ppm). The first response 628 is a control, whilethe second response 626 is a 3A. FIG. 6C is a diagram 640 of water at100 ppm at 1 bar. In this diagram 640, a first response 648 and a secondresponse 646 are shown along a time axis 642 in minutes and aconcentration axis 644 in parts per million (ppm). The first response648 is a blank sample, while the second response 646 is a 3A sample.

The initial sharp front of water breakthrough is proportional to theadsorption rate. The steeper the curve, the higher is the value of themass transfer coefficient. The residence times for these experiments areless than 100 ms. No water bypasses prior to breakthrough. These confirmthat fast kinetics observed for various partial water pressure of 10000ppm (1%), 1890 ppm, and 100 ppm at 1 bar. The water capacity estimatedat the breakthrough is about 9.5 millimole/gram, 10.5 millimole/gram,and 8 millimole/gram, correspondingly. Because the ultimate capacityfrom water isotherm is known to be 12.2 millimole/gram, 11millimole/gram, 8.5 millimole/gram for three examples, the ratio ofadsorption capacity at breakthrough is more than 75% of the ultimateswing adsorption capacity, which are in the preferred range and the timefor equilibration was less than 30 milliseconds which is nearly in themost preferred range.

Example 3 is an example that provides evidence of fast kinetics for acommercial zeolite 3A crystals bounded on a capillary column withbinder. The zeolite 3A crystals are from the same batch used in example1.

To further establish that structured adsorbents may have rapid kinetics,more ballistic tests with bound 3A crystal coated on interior surface of530 micron internal diameter (ID) capillary column was performed tovalidate fast water kinetics. FIG. 7 is an exemplary diagram 700 ofwater breakthrough results on a 3A zeolite capillary column. In thisdiagram 700, a first response 706 and a second response 708 are shownalong a time after water exposure axis 702 in minutes and a relativeabundance axis 704. The first response 706 is a blank glass capillarycolumn, while the second response 708 is a 3A zeolite capillary column.This diagram 700 represents that breakthrough results on 3A coated in athin film, which has thickness of 15 microns. The residence time isabout 290 milliseconds (ms) for this run, and the slope of waterbreakthrough curve is substantially similar to the control curve. Thisexample shows that for a formulated (bound) zeolite film the kineticscan be less than 100 milliseconds, (one-third of residence time) whichprovides sharp fronts and is in a kinetically preferred range.

Example 4 is an example that provides evidence of high water capacity onthe same batch of zeolite 3A crystals used in Example 1. FIG. 8 is anexemplary diagram 800 of water isotherms on 3A zeolite crystal overtemperature (25° C. to 200° C.) and water pressure ranges (0 to close tosaturated pressure). The wide range of temperature measurement providesdata for design basis for a TSA cycle, and the wide range of pressuremeasurements additionally provides data for the design basis for deepdehydration cycles to sub ppm level additionally utilizing pressureswing. In this diagram 800, various responses 806, 808, 810, 812, 814and 816 are shown along a pressure axis 802 in bars and a loading axis804 in milli moles per gram (mmol/g). The first response 806 is for a25° C., the second response 808 is for a 50° C., the third response 810is for 100° C., the fourth response 812 is for 150° C., the fifthresponse 814 is for 200° C. and the sixth response 816 is for 250° C.

The responses 806, 808, 810, 812, 814 and 816 of the isotherms of 3Azeolite crystals involve a wide range of temperatures and pressures. Aswater removal for LNG specifications has to meet 0.1 ppmv, waterisotherms have been measured down to this range for design purposes.High capacity of water over 3 moles per kilogram (mol/kg) on 3A at 1e-5bar water pressure is shown at room temperature.

With rapid kinetics, processes may be configured to approximateinstantaneous equilibration between the water fugacity in the gas phaseand that in the zeolite crystal and/or structured adsorbent (e.g.,crystals and binder formatted into a thin layer) provided kinetics ofthe adsorber system is sufficiently fast. Because only water goes intothe 3A crystal, the process operating conditions can be calculatedwithout having to account for competitive adsorption in the 3A crystal.

Example 5 is an example that provides evidence of good foulingresistance on the same batch of zeolite 3A that was used in Example 1.This batch of crystals have kinetics that are nearly in the mostpreferred operating range.

To experimental demonstrate fouling tolerance, zeolite 3A samples wereexposed to a variety of contaminants at high pressures in a fouling testunit. In the fouling test unit, a base high pressure gas mixture wasdoped with individual foulants. The base gas mixture has the compositionof 6.08% ethane, 1.90% propane, 0.16% n-butane, 0.13% isobutene, 0.01%isopentane, 0.01% hexane and 91.7% methane. Foulants studied were heavyhydrocarbons, TEG (Triethylene glycol), MDEA (Methyl Di-Ethanol Amine),MEA (Mono Ethyl Amine), and methanol. Fouling was accessed usingbreakthrough experiments with short residence time and TGA measurementof water uptake. No change in kinetics or adsorption capacity wasdetected in fouled samples.

Another enhancement in using zeolite 3A is the fouling resistance forcontaminants. As noted above, conventional systems utilize silica gel,activated alumina, and molecular sieves as adsorbents. Unlike molecularsieves, silica gel and activated alumina have larger pores and opensurfaces and have a wide distribution of pore sizes in the range between100 nanometers (nm) and 500 nm. The pores sizes of the zeolite molecularsieves type 3A, 4A, 5A, and 13X are approximately 0.3 nm, 0.4 nm, 0.5nm, and 1.0 nm, respectively. Water molecules, with an approximatemolecular diameter of 0.28 nm, can easily penetrate the pores of themolecular sieve 3A adsorbent, while other hydrocarbons, including CO₂(e.g., about 0.35nm) and CH₄ (e.g., about 0.36 nm), are not readilyadsorbed in the zeolite 3A, but are able to penetrate the pores ofzeolite 4A and 5A. Accordingly, the utilization of zeolite 3A canprovide an enhanced foulant resistance material compared to zeolite 4Aand zeolite 5A. Thus, zeolite 3A is expected to be more foulingtolerant, as compared to other adsorbents.

Example 6 is an example that provides evidence that extra frameworkaluminum and loss of crystallinity can completely destroy the kineticand reduce the measurable water adsorption capacity to zero.

A commercial zeolite 4A material with fast kinetic and goodcrystallinity was ion exchanged to a zeolite 3A material. The ionexchange procedure used the following steps: 1) adding 10 gram (g) 4Azeolite into 100 milliliter (ml) of deionized H₂O and then add 10 g ofKCl into the mixture held in a glass beaker while mixing with a stirbar; 2) adjusting the pH to 5 using dilute HCl/NH₄OH as a buffer; 3)adjusting the temperature to 60° C. to 80° C. and stir covered for onehour; 4) filtering and washing with deionized water; 5) drying in 115°C. oven then calcine for three hours at 350° C.; 6) repeating steps 1 to5 for two additional times. Inductive Couples Plasma EmissionSpectroscopy (ICP) results show this sample has about 92 mole % K withthe balance being Na.

The ion exchanged sample was determined to have significantly degradedperformance that was due to extra framework of Al and lack of fullcrystallinity. Degradation of crystallinity and formation of extraframework Al occurred during the ion exchange procedure that used abuffer solution to set the pH to 5. The extra framework Al was measuredwith NMR and the lack of full crystallinity in the zeolite was measuredwith x-ray diffraction (XRD). FIG. 10 is an exemplary diagram 1000 ofthe Al NMR spectrum. Response 1006 in FIG. 10 shows recorded NMRspectrum of the ion exchanged sample. It is seen that there is a largeand small peak in the spectrum. The small peak is a resonance at about 4ppm and is due to non-framework alumina in the ion exchanged sample. Theintensity of the peak compared to the large peak represents about 6.4%of the aluminum in the sample being non-framework. Also, the maintetrahedral peak at 58 ppm is very broad indicating that the tetrahedralalumina species are highly distorted due to strain in the crystals frompartial loss of crystallinity. This degree of non-framework aluminumoutside of the preferred ranges for fast kinetics.

FIG. 11 is an exemplary diagram 1100 of the XRD pattern that shows thesample has lost crystallinity. The XRD pattern 1106 is from the ionexchanged sample and the XRD pattern 1104 is from a highly crystallineion exchanged sample that is discussed in Example 7. The presence ofamorphous material in the XRD pattern 1106 is indicated by the hump inthe baseline between 20° and 36° two-theta (2θ). X-ray diffraction canbe used to assess the crystallinity of a zeolite sample. Amorphousmaterial in the sample are indicated as a broad diffuse peak in thex-ray diffraction pattern. When the x-day diffraction pattern isrecorded using Cu K-alpha radiation the broad peak from amorphousmaterials appears as a maximum at a two-theta of 28. Subtracting thebaseline in the diffraction pattern provides a measure of the amplitudeof this amorphous peak at two-theta of near 24. The ratio of this to thestrong sharp peak at a two-theta of near 28 is estimated to be 0.4. Theratio of this to the second strong sharp peak at a two-theta of near 30is estimated to be 0.5. This ratio provides a measure of the amount ofamorphous material in the sample. It is greater than the preferred rangeof ratio which is less than 0.2.

The ion exchanged material of this example shows negligible watercapacity based on four instruments: two gravimetric instruments thatmeasure equilibrium water adsorption, and the two ballisticchromatography units described in Examples 1 and 2. In the ballisticchromatography units the breakthrough is very similar to control (e.g.,a blank) experiment with breakthrough time less than 10 secondsdifferent from the control. Results from one gravimetric instrument areshown in 1306 of FIG. 13, which is discussed further below. It showsthat the uptake is nearly zero at all water activities. As such, thisexample provides evidence that extra framework Al and reducedcrystallinity is deleterious to performance. This degradation occurredwith a relatively standard ion exchange process that used a buffersolution to control pH.

Example 7 is an example that provides evidence of reasonably fastkinetics for a zeolite 3A sample with a high K content of 98% and goodcrystallinity. The sample used in this example was ion exchanged fromzeolite 4A without using the buffer solution employed in Example 6(e.g., the procedure was the same as in Example 6 with the omission ofstep number 2).

FIG. 10 is an exemplary diagram 1000 showing Al NMR spectra used todetect extra framework Al. The ion exchanged sample from this example isspectra 1004. It is shown that there is one narrow resonance at 59 ppmindicating a fully crystalline material in which all the alumina is inhighly symmetrical tetrahedral framework environments (e.g., nodetectable extra framework Al).

Examination of the powder XRD shows the sample has good crystallinitybased on the sharp high intensity peaks and the absence of a broadamorphous peak centered at a two-theta of 28. FIG. 11 is an exemplaryXRD diagram 1100. The absence of any noticeable hump in the XRD pattern(line 1104) of 3A sample along with the strong intensities of the peaksindicates that sample is fully crystalline. The ratio of the amplitudeof hump to the strong sharp peak at a two-theta of near 30 is almostzero. As such this sample has good crystallinity and falls within thepreferred ratio of the amorphous to crystalline peak intensity of lessthan 0.05.

To establish the intrinsic kinetic of zeolite 3A ballisticchromatography, small packed adsorbent bed of zeolite crystals (e.g., 3milligram (mg) to 10mg) were reviewed to measure breakthrough in a shortresidence time. FIG. 14 is a diagram 1400 of the water breakthrough on a3A packed adsorbent bed. In this diagram 1400, a first response 1406 anda second response 1408 are shown along a time after water exposure axis1402 in minutes and a relative abundance axis 1404. In this diagram1400, the breakthrough curves of 3A samples at water concentration of2.3% in a packed bed configuration along with the associated blankconfigurations. The first response 1406 is for a blank configuration,while the second response 1408 is for 3A packed bed. The data isrelatively flat before the breakthrough front, with no initial bleedthrough of water. Thus, the uptake of water is as much faster than theresidence time of the water in the sample beds. To achieve this type ofperformance, the sample has to equilibrate with the flow gas stream in atime that is at least five times shorter than the residence time of gasthrough the sample bed. In the diagram 1400, the residence times are 81milliseconds through the packed bed. Because there was a relativelysharp breakthrough fronts with good swing adsorption capacity, the timeto equilibrate water vapor with the zeolite 3A sample was less thanabout one-third of the residence time or less than 27 milliseconds. Theblank response 1406 is faster than the 3A packed bed response 1408. Tocalculate the fraction of the ultimate capacity at breakthrough, theconcentration after breakthrough is adjusted by the response of theblank. The swing adsorption capacity at breakthrough is 8.9 mole/kg,more than 75% of the ultimate swing adsorption capacity of 10.5 mole/kg.As such, the kinetics of the sample are nearly in the most preferredrange. The theta parameter (θ) for this breakthough curve was determinedto be 0.7 indicating that its kinetics are not as good as the sample inExample 1. However, the kinetics are still in a preferred range, but notthe most preferred range that enable ultra-fast swing adsorptionprocesses.

Example 8 is an example that provides evidence of reasonable kineticsand lower adsorption capacity in a zeolite 3A sample with a K content of81% and somewhat reduced crystallinity. This sample was ion exchangedfrom the zeolite 3A sample from example 1. The ion exchange processyielded a sample with 81% K cations with the balance of the cationsbeing Na and slightly reduced the crystallinity. FIG. 12 is an exemplarydiagram 1200 of an exemplary XRD spectra recorded with Cu K radiation.In FIG. 12, response 1206 is the XRD spectra of the parent 3A andresponse 1208 is the XRD spectra of the ion exchanged material of thisexample. The calculated mass absorption coefficient, μ, for 40% K (e.g.,spectra response 1206) LTA is 41.7 centimeter squared per gram (cm²/g),while for 81% K exchanged LTA (e.g., spectra response 1208), μ=52.6cm²/g.)

The presence of amorphous material in the XRD pattern in response 1208is indicated by the hump in the baseline between 20° and 36° two-theta(2θ), peaking at a two-theta of 28 degrees. Subtracting the baseline inthe diffraction pattern provides a measure of the amplitude of thisamorphous peak at two-theta of near 28. The ratio of this to the strongsharp peak from the ion exchanged zeolite 3A at a two-theta of near 24degrees is estimated to be 0.1. The ratio of this amorphous peak to thesecond strong sharp peak at a two-theta of near 30 degrees is estimatedto be 0.09. This ratio provides a measure of the amount of amorphousmaterial in the sample. It is within an allowable range for goodcrystallinity, but outside the most preferred range. The parent materialshown in spectra response 1206 has almost no detectable amorphous peakand the ratio of the amorphous to crystalline peaks falls within themost preferred range (e.g., the parent was highly crystalline).

Compared XRD pattern of this 3A sample with its parent material ofcommercial 3A (same used in example 1) shows this 3A sample has someloss of crystallinity from the reduced intensities of the peaks althoughthe direct comparison is not as valid because the compositions havechanged. The calculated mass absorption coefficient, μ, for 41% K ex.LTA is 41.7 centimeter squared per gram (cm²/g), while for 81% K ex.LTA, μ=52.6 cm²/g for Cu K radiation.)

To establish the intrinsic kinetic of zeolite 3A ballisticchromatography, small (e.g., 3 milligram (mg) to 10mg) packed adsorbentbed of zeolite crystals were reviewed to measure breakthrough in a shortresidence time. FIG. 15 is a diagram 1500 of the water breakthrough on a3A packed adsorbent bed. In this diagram 1500, a first response 1506 anda second response 1508 are shown along a time after water exposure axis1502 in minutes and a relative abundance axis 1504. In this diagram1500, the breakthrough curves of 3A samples at water concentration of2.3% in a packed bed configuration along with the associated blankconfigurations. The first response 1506 is for a blank configuration,while the second response 1508 is for 3A packed bed. The data isrelatively flat before the breakthrough front, with no initial bleedthrough of water. Thus, the uptake of water is faster than the residencetime of the water in the sample beds. To achieve this type ofperformance, the sample has to equilibrate with the flow gas stream in atime that is at least five times shorter than the residence time of gasthrough the sample bed. In the diagram 1500, the residence times areabout 60 milliseconds through the packed bed. Because there was arelatively sharp breakthrough fronts with good swing adsorptioncapacity, the time to equilibrate water vapor with the zeolite 3A samplewas less than about one-third of the residence time or less than 20milliseconds. The blank response 1506 is faster than the 3A packed bedresponse 1508. To calculate the fraction of the ultimate capacity atbreakthrough, the concentration after breakthrough is adjusted by theresponse of the blank. The swing adsorption capacity at breakthrough is4.7 mole/kg, more than 75% of the ultimate swing adsorption capacity of5.74 mole/kg, which is significantly reduced from the parent materialshown is Example 1. The kinetics of the sample are nearly in the mostpreferred range. The theta parameter (θ) for this breakthough curve wasdetermined to be 0.85 indicating that its kinetics are not as good asthe sample in Example 1. However, the kinetics are still in a preferredrange, but not the most preferred range that enable ultra-fast swingadsorption processes.

Example 9 is an example that provides a comparison of water isothermsfor 3A samples with different K content. FIG. 13 is a diagram 1300 ofwater isotherms for different samples. Sample A is has about 92 mole % Kand was described in example 6. Sample B has about 98 mole % K, and wasdescribed in example 7. Sample C has about 81 mole % K, and wasdescribed in example 8. Sample ALFA 3A has 40% K and was described inExample 1. In FIG. 13, sample A measurements are labeled 1306, sample Bmeasurements are labeled 1310, sample C measurements are labeled 1308,and ALFA 3A are labeled 1312. The x-axis (pressure) 1302 and the y-axis(loading in mole per kilogram) 1304 are shown in the diagram 1300. Wateruptake measurements 1306 show the sample A with a significant amount ofextra framework Al and significantly reduced crystallinity hasnegligible water uptake. Measurements for sample C 1308, which has someloss of crystallinity, show a decreased water uptake, about 20% to 30%lower compared to its parent material—ALFA 3A. Also, measurements 1308of sample B (e.g., are about 98% K) shows similar, but slightly lowerwater capacity on a weight basis compared to ALFA 3A which has about 41%K. Given the calculated density for 41% K-LTA is 1.59 g/cc while for 98%K-LTA is density is 1.69 g/cc, the small difference of 5% to 10% isexpected from the density difference of 6%.

Example 10 is an example that illustrates an alternative method toassess the fouling tolerance of different zeolite 3A samples. Theisotherm of CO₂ measured when the sample has equilibrated with CO₂ for atime of less than 3 minutes is used to assess fouling tolerance. The CO₂isotherm measurements were performed using a commercial volumetricadsorption system (Quantochrome Autosorb). Measurements were performedat 25° C. after samples had been heated to 350° C. for 4 hours undervacuum to remove adsorbed water that reduces CO₂ uptake. CO₂ is largerthan the effective pore size of all 3A samples studied and as such hasslow kinetics. All foulant molecules have molecular sizes larger thanCO₂. Due to slow kinetics for CO₂ in 3A samples, the system cannot reachequilibrium in practical time frame. Instead, an equilibration time ofabout 3 minutes was used for each point on the isotherm. FIG. 16 showscomparison of CO₂ capacity at this non-equilibrium conditions for 3Awith different K content. In this diagram 1600, the kinetically limiteduptake of CO₂ in 3A samples can be quantified with K content in thesamples. The higher the K content, the lower CO₂ capacity. This showspreferable K content in 3A are needed for fouling tolerance.

FIG. 16 is another exemplary diagram of the CO₂ non-equilibrium isothermmeasurements for different zeolite 3A samples. In this diagram 1600, aplot of the CO₂ non-equilibrium isotherm measurements for differentzeolite 3A samples is shown along a pressure axis 1602 in torrs and aloading axis 1604 in mol/kg. The isotherm 1612 is for a zeolite samplehaving about 98 mole % K that was described in example 7, while theisotherm 1610 is for a sample with about 81 mole % K that was describedin example 8. The isotherm 1608 is for a zeolite 3A sample that was ionexchanged to have 47% K, while the isotherm 1606 is for a zeolite 3Asample that was ion exchanged to have 35% K. To have sufficient foulingtolerance, it is preferred the have a CO₂ capacity (25° C. and less than3 minute equilibration times in isotherm measurement) of less than 2milli moles/gram at 760 ton. A more preferred fouling tolerance is a CO₂loading in an isotherm measurement (at 25° C. with less than 3 minuteequilibration times) of less than 1.5 millimole/gram at 760 ton. An evenmore preferred fouling tolerance is a CO₂ loading in an isothermmeasurement (at 25° C. with less than 3 minute equilibration times) ofless than 0.5 millimole/gram at 760 torr. For rapid cycle swingadsorption processes, the residence time for gas contacting theadsorbent material in the adsorbent bed during the adsorption step isless than 2.5 seconds, preferably less than 0.5 seconds and even morepreferably less than 0.1 seconds.

Example 11 is yet another example based on Examples 1 to 10 and otherdata on the performance of different Zeolite 3A samples in rapid cycleswing adsorption processes used for rigorous dehydration. The groupingis based on a characteristic of the zeolite crystal quality. Zeolite 3Acrystals with good crystal quality have less than 10% extra framework Alas measured by NMR and/or in and XRD pattern recorded with Cu Kradiation a ratio of the amorphous peak height (or intensity) to eitherof the neighboring peaks (two-theta equals about 24 degrees or about 30degrees) being less than 0.2. Zeolite 3A crystals with very good crystalquality have less than 5% extra framework Al as measured by NMR and/orin and XRD pattern recorded with Cu K radiation a ratio of the amorphouspeak height (or intensity) to either of the neighboring peaks (two-thetaequals about 24 degrees or about 30 degrees) being less than 0.1.Zeolite A crystals with very excellent crystal quality have less than 1%extra framework Al as measured by NMR and/or in and XRD pattern recordedwith Cu K radiation a ratio of the amorphous peak height (or intensity)to either of the neighboring peaks (two-theta equals about 24 degrees orabout 30 degrees) being less than 0.05. It is most preferred to usecrystals with excellent crystal quality. This is particularly true inrapid cycle swing adsorption rigorous dehydration processes where theresidence time for gas contacting the adsorbent material in theadsorbent bed during the adsorption step is preferably less than 0.1seconds. The use of excellent quality crystals enhances kinetics andallows the use of the most fouling tolerant K cation contents to providethe most fouling tolerant rapid cycle in rapid cycle swing adsorptionrigorous dehydration processes. With excellent quality crystals the Kcation content can be as high as 1.0 in a swing adsorption process withthe residence time for gas contacting the adsorbent material in theadsorbent bed during the adsorption step is being less than 2.5 seconds.With excellent quality crystals the K cation content can be as high as98% in a swing adsorption process with the residence time for gascontacting the adsorbent material in the adsorbent bed during theadsorption step is being less than 0.5 seconds. With very good crystalquality the cation content for rapid cycle swing adsorption rigorousdehydration processes should be in a range from 35% to 85%. It should benoted that a cation content of 35% is defined to be a K/Al ratio of0.35.

Example 12 is an example that provides evaluation of fast water kineticsfor the zeolite 3A crystals studied in example 1 with aconcentration-swing frequency response unit. By incorporation of large3A synthesized crystals (e.g., with the crystal size approximately 10times larger), the water transport diffusivity can be obtained through amacroscopic method and thus compared for the 3A samples with different Kcontents. Preferably, the fast water kinetics may be maintained throughmicron-size crystals.

To evaluate the water kinetics in 3A crystal, a concentration frequencyresponse method has been utilized in addition to breakthrough methoddescribed in example 2. The centration frequency response method isknown to those skilled in the art. See e.g., Wang Y, LeVan MD, Mixturediffusion in nanoporous adsorbents: Development of Fickian fluxrelationship and concentration-swing frequency response method,Industrial & Engineering Chemistry Research. Mar 28 2007; 46(7): p. 2141to 2154. The operation of the method is similar to that noted above inrelation to FIG. 5. The helium gas flows through a sparger 508 toprovide a saturated vapor feed at pre-set temperature. The flow rate iscontrolled by MFC 502 to vary sinusoidally. The resulting stream is thenmixed with another line of helium with a sinusoidal flow rate controlledby MFC 506 with the same amplitude perturbation, but in reverse phase. Athird line of helium, which has the flow rate controlled by MFC 504, isoptional to provide a further dilution of feed concentration. Theperturbation of flow rate is maintained small to maintain a linearsystem for analysis. The total pressure is also controlled constantly bythe pressure controller 512. Therefore, the total inlet flow rate andthe pressure in the adsorption system are constant, but the inletconcentration is a time-varying sinusoidal wave. The concentrationvariation causes the gases to diffuse into or out of the sample (e.g.,3A crystals), where they adsorb and desorb, which causes the molefractions outside of the sample and the flow rate out of the sample tochange. The mole fractions in the effluent of the sample respond in aperiodic sinusoidal manner, which is recorded and measured by a massspectrometer 514. The amplitude ratio of outlet and inlet composition isused to extract mass transfer rates from the mathematical models. Thesystem may also be configured to perform regeneration in-situ and hasflexibility to perform experiments at various concentrations andoperating conditions of temperatures and pressures.

To evaluate fast kinetics, the system volume is maintained small (e.g.,less than several cm³) to allow fast perturbation and detection up to 1hertz (Hz) by Agilent MS 5977. By way of example, for the water kineticsstudy, about 9 milligrams (mg) 3A crystals are packed in a zero lengthcolumn type bed. This configuration may lessen or eliminate axialdispersion effect and provides a simple model to extract mass transferrates. The flow-through mode minimizes heat effects which has been shownin previous publications.

FIG. 17 is an exemplary diagram 1700 of frequency response curves forwater on commercial 3A crystals and control experiments at partial waterpressure of 0.009 bar. The 3A crystals may have a radius of 1 to 2micrometers (μm). In diagram 1700, a first response 1706 and a secondresponse 1708 are shown along a frequency axis 1702 in hertz (Hz) and anamplitude ratio axis 1704, which is the ratio of outlet composition toinlet composition (Y_(out) to Y_(in)). The first response 1706 and asecond response 1708 are results from a concentration frequency response(CSFR) unit for water concentration at 0.01 bar. In this diagram 1700,the axis 1702 is the perturbation frequency and the axis 1704 is theamplitude ratio of outlet and inlet composition. The square symbolsrepresent a control experiment, which is performed in an empty bed,while the circles represent the response curve on a bed having 3Acrystals. The first response 1706 is a best fit (e.g., a fit within thethreshold) from a diffusion model with diffusion time constants fastthan 0.1 second for measurement points (e.g., a surface diffusion (SD)fit: D/r² greater than 0.1 per second), while the second response 1708is the control fit to the control points.

FIG. 18 is an exemplary diagram 1800 of a sensitivity analysis forfrequency response experiments on H₂O on commercial 3A crystals at apartial water pressure of 0.009 bar. In diagram 1800, a first response1806, a second response 1808, a third response 1810 and a fourthresponse 1812 are shown along a frequency axis 1802 in hertz (Hz) and anamplitude ratio axis 1804, which is the ratio of outlet composition toinlet composition (Y_(out) and Y_(in)). This diagram 1800 describes thesensitivity analysis on the system for various diffusion time constantsranging from 1e-3 (e.g., 1×10⁻³) per second to 1 per second. The systemclearly differentiates kinetics for diffusion time constants slower than0.1 second. For example, the second response 1808 represents the curvefor 0.001 per second (e.g., a micropore diffusion (MD) or surfacediffusion (SD) fit: D/r² equal to 0.001 per second), which behaves quitedifferently from the response curve 1810 that represents the curve for0.01 per second (e.g., a surface diffusion (SD) fit: D/r² equal to 0.01per second). However, once kinetics become fast enough, the systemreaches the detection limit and thus the curves becomes very similar forthe fourth response 1812 that represents 0.1 per second (e.g., a surfacediffusion (SD) fit: D/r² equal to 0.1 per second) and the first response1806 that represents 1 per second (e.g., a surface diffusion (SD) fit:D/r² equal to 1 per second). Therefore, it may be validated that thewater on 3A crystals has diffusion time constants per radius squared(D/r²) faster than 0.1 per second, wherein the radius is of thecrystals. For the sample with crystal radius of about 1 to 2 microns, asshown in FIG. 2A and 2B, the transport diffusivity of water on 3A isshown to be faster than 1e-13 meter squared per second (m²/s).

To accurately determinate the transport diffusivity with macroscopicmethods, one approach is to synthesize large crystals to aid diffusionmeasurements in zeolites, as the diffusion time constants decrease withthe increase of the radius of the crystal size (e.g., as the square ofradius (r²) increases). Thus, larger crystal size 4A has beensynthesized and then exchanged to have 3A crystal samples with twolevels of potassium K content, such as 48% K content and 81% K content,respectively. FIGS. 19A and 19B are exemplary SEM diagrams 1900 and 1920of an adsorbent material. The SEM images are shown for these two samplesin diagrams 1900 and 1920 with an average size estimated to be in arange between 10 μm and 20 μm.

Further, FIG. 20 is an exemplary diagram 2000 of frequency responsecurves for water on larger crystal size 3A with 48% K at a partial waterpressure of 0.009 bar. In diagram 2000, symbols represent experimentaldata (e.g., circles represent H₂O on 3A and squares represent a controlempty bed), while the responses 2006, 2008 and 2010 represent the modelfits to the experimental data, which are shown along a frequency axis2002 in hertz (Hz) and an amplitude ratio axis 2004, which is the ratioof outlet composition to inlet composition (Y_(out) to Y_(in)).Specifically, the first response 2006 represents a micropore diffusion(MD) fit, with the second response 2008 represents a fit control and thethird response 2010 represents micropore diffusion (MD) fit with twocrystal size fit. In the diagram 2000, CSFR results for H₂O on largecrystal size 3A with 48% K at 1% water feed concentration. The response2006 (e.g., the solid line), which is the micropore diffusion model fit,represents the experimental data reasonably well. The extracteddiffusion time constants (D/r²) is about 0.007 per second. Withestimated crystal size of 12 um, the diffusivity for water on 3A isabout 9E-13 m²/s. This suggests that the time to reach 50% equilibriumin the samples with smaller crystals (1 micron radius) is less than0.033 seconds and the time to reach full equilibrium is less than 0.10seconds. It is expected to have faster water diffusivity at higher waterconcentration and slower diffusivity at lower concentration based onDarken equation. See, e.g., Do, D. D., Adsorption Analysis: Equilibriumand Kinetics, 1998, Imperial College Press, London, p. 412. As thefrequency response is unique to determine the dominating resistance, thebetter description from micropore diffusion with parallel sites, shownin black dashed line, independently indicates the existence of thebimodal distribution of crystal sizes, which has been confirmed by theSEMs in FIGS. 19A and 19B. See, e.g., Song L, Rees LVC, FrequencyResponse Measurements of Diffusion in Microporous Materials, Mol Sieves.Vol 7: Springer-Verlag

Berlin Heidelberg; 2007: p. 235 to 276. The diffusivity has beenextracted to have values of 9e-13 m²/s with crystal size distributed intwo regions, such as one having larger crystal sizes around about 20 umin parallel to small crystals around about 1 micron range.

FIG. 21 is an exemplary diagram 2100 of frequency response curves forwater on larger crystal size 3A with 81%K. In diagram 2100, symbolsrepresent experimental data (e.g., circles represent H₂O on 3A (81%K)and squares represent a control empty bed), while the responses 2106,2108, 2110 and 2112 represent the model fits to the experimental data,which are shown along a frequency axis 2102 in hertz (Hz) and anamplitude ratio axis 2104, which is the ratio of outlet composition toinlet composition (Y_(out) to Y_(in)) Specifically, the first response2106 represents a fit control, the second response 2108 represents alinear driving force (LDF) fit, the third response 2110 is a microporediffusion (MD) with two crystal sizes, and the fourth response 2112represents a micropore diffusion (MD) fit. In the diagram 2100, akinetics study on the large crystal size of 3A with higher K content of81% is shown. The data is best described by the parallel microporediffusion model, compared to surface barrier model represented by LDFand a single site micropore diffusion model. The extracted diffusivitiesbased on average crystal size is about 5e-13 m²/s, which drops about 50%compared to 3A with lower K content of 48%. Accordingly, the comparisonindicates that the diffusivities slightly decrease with increase of Kcontent for the range studied under 80% K.

In certain configurations, the present techniques may be utilized in aswing adsorption process (e.g., a rapid cycle process) for the removalof one of more contaminants from a feed stream. In particular, thepresent techniques involve a one or more adsorbent bed units to performa swing adsorption process or groups of adsorbent bed unit configured toperform a series of swing adsorption processes. Each adsorbent bed unitis configured to perform a specific cycle, which may include anadsorption step and a regeneration step. By way of example, the stepsmay include one or more feed steps, one or more depressurization steps,one or more purge steps, one or more recycle steps, and one or morere-pressurization steps. The adsorption step may involve passing a feedstream through the adsorbent bed to remove contaminants from the feedstream. The regeneration step may include one or more purge steps, oneor more blowdown steps, one or more heating steps and/or one or morerepressurization steps.

The present techniques may also include adsorbent materials that areconfigured to perform at various operating conditions. For example, thefeed pressure may be based on the preferred adsorption feed pressure,which may be in the range from 400 pounds per square inch absolute(psia) to 1,400 psia, or in the range from 600 psia to 1,200 psia. Also,the purge pressure may be based on the sales pipeline pressure, whichmay be in the range from 400 psia to 1500 psia, in the range from 600psia to 1200 psia.

By way of example, FIG. 22 is a three-dimensional diagram of the swingadsorption system 2200 having six adsorbent bed units andinterconnecting piping. While this configuration is a specific example,the present techniques broadly relate to adsorbent bed units that can bedeployed in a symmetrical orientation, or non-symmetrical orientationand/or combination of a plurality of hardware skids. Further, thisspecific configuration is for exemplary purposes as other configurationsmay include different numbers of adsorbent bed units. In thisconfiguration, the adsorbent bed units may include adsorbent materials,which may preferably be formed as adsorbent bed such as a substantiallyparallel channel contactor.

In this system, the adsorbent bed units, such as adsorbent bed unit2202, may be configured for a cyclical swing adsorption process forremoving contaminants from feed streams (e.g., fluids, gaseous orliquids). For example, the adsorbent bed unit 2202 may include variousconduits (e.g., conduit 2204) for managing the flow of fluids through,to or from the adsorbent bed within the adsorbent bed unit 2202. Theseconduits from the adsorbent bed units 2202 may be coupled to a manifold(e.g., manifold 2206) to distribute the flow of the stream to, from orbetween components. The adsorbent bed within an adsorbent bed unit mayseparate one or more contaminants from the feed stream to form a productstream. As may be appreciated, the adsorbent bed units may include otherconduits to control other fluid steams as part of the process, such aspurge streams, depressurizations streams, and the like. Further, theadsorbent bed unit may also include one or more equalization vessels,such as equalization vessel 2208, which are dedicated to the adsorbentbed unit and may be dedicated to one or more step in the swingadsorption process.

In certain configurations, the adsorbent material may be utilized in anadsorbent bed unit that includes a housing, which may include a headportion and other body portions, that forms a substantially gasimpermeable partition. The housing may include the adsorbent material(e.g., formed as an adsorbent bed or substantially parallel channelcontactor) disposed within the housing and a plurality of valves (e.g.,poppet valves) providing fluid flow passages through openings in thehousing between the interior region of the housing and locationsexternal to the interior region of the housing. Each of the poppetvalves may include a disk element that is seatable within the head or adisk element that is seatable within a separate valve seat insertedwithin the head (not shown). The configuration of the poppet valves maybe any variety of valve patterns or configuration of types of poppetvalves. As an example, the adsorbent bed unit may include one or morepoppet valves, each in flow communication with a different conduitassociated with different streams. The poppet valves may provide fluidcommunication between the adsorbent bed or substantially parallelchannel contactor and one of the respective conduits, manifolds orheaders. The term “in direct flow communication” or “in direct fluidcommunication” means in direct flow communication without interveningvalves or other closure means for obstructing flow. As may beappreciated, other variations may also be envisioned within the scope ofthe present techniques.

The adsorbent bed or substantially parallel channel contactor comprisesadsorbent material formed into the adsorbent material, which is capableof adsorbing one or more components from the feed stream. Such adsorbentmaterials are selected to be durable against the physical and chemicalconditions within the adsorbent bed unit and can include metallic,ceramic, or other materials, depending on the adsorption process.

By way of example, a cyclical rapid cycle swing adsorbent system forremoving water from a gaseous feed stream may include one or moreadsorbent bed units. Each of the adsorbent bed units may include: ahousing forming an interior region; a substantially parallel channelcontactor disposed within the interior region of the housing, whereinthe substantially parallel channel contactor comprises an adsorbentmaterial being a zeolite 3A having (i) a K to Al atomic ratio is in arange between 0.3 and 1.0; and (ii) a Si to Al atomic ratio is in arange between 1.0 and 1.2; a plurality of valves secured to the housing,wherein each of the plurality of valves is in flow communication with aconduit and configured to control fluid flow along a flow path extendingfrom a location external to the housing through the conduit and to thesubstantially parallel channel contactor through the valve. The housingmay be configured to maintain a pressure within the range between 400pounds per square inch absolute (psia) and 1500 psia.

Further, additional enhancements may also be provided. For example, therapid cycle swing adsorption system is configured to perform a rapidcycle pressure swing adsorption process to dehydrate a gaseous feedstream; to perform a rapid cycle temperature swing adsorption process todehydrate a gaseous feed stream and/or to perform a rapid cycle partialpressure swing adsorption process to dehydrate a gaseous feed stream.Also, the rapid cycle swing adsorption system may be configured toperform a cycle duration that is greater than 2 seconds and less than300 seconds, and may be configured to provide a residence time for gasin the gaseous feed stream contacting the adsorbent material in thesubstantially parallel channel contactor during the adsorption stepbeing less than 2.5 seconds, less than 0.5 seconds. The rapid cycleswing adsorption system may be configured to provide a product streamhaving a concentration of water in the product stream is less than 50parts per million on a mole basis or less than 1 parts per million on amole basis.

Further, the additional enhancements may also be provided in thesubstantially parallel channel contactor. For example, the adsorbentmaterial has the K to Al atomic ratio is in a range between 0.35 and0.98 or in a range between 0.4 and 0.8. The adsorbent material may havegreater than 50% of the non-potassium cations in the zeolite 3A are Na,greater than 80% of the non-potassium cations in the zeolite 3A are Naor greater than 90% of the non-potassium cations in the zeolite 3A areNa. Also, the adsorbent material may be fouling tolerant, whereinfouling tolerant may be defined as the adsorbent material having a CO₂capacity at 25° C. and less than 3 minute equilibration times inisotherm measurement of less than 2 milli moles/gram at 760 ton or maybe defined as the adsorbent material having a CO₂ capacity at 25° C. andless than 3 minute equilibration times in isotherm measurement of lessthan 0.5 milli moles/gram at 760 torr. Further, the average size ofzeolite aggregates in the zeolite 3A may be less than 40 microns or lessthan 10 microns. In addition, the zeolite 3A may comprise very goodquality crystals or excellent quality crystals.

In yet another configuration, a substantially parallel channel contactormay be formed from the adsorbent material. The adsorbent material is azeolite 3A having (i) a K to Al atomic ratio is in a range between 0.3and 1.0; and (ii) a Si to Al atomic ratio is in a range between 1.0 and1.2. The adsorbent material has the K to Al atomic ratio is in a rangebetween 0.35 and 0.98 or in a range between 0.4 and 0.8. In addition,the zeolite 3A may comprise very good quality crystals or excellentquality crystals.

In certain configurations, the swing adsorption system, which includesthe adsorbent material, may process a feed stream that predominatelycomprises hydrocarbons along with one or more contaminants. For example,the feed stream may be a hydrocarbon containing stream having greaterthan one volume percent hydrocarbons based on the total volume of thefeed stream. Further, the feed stream may include hydrocarbons alongwith H₂O, H₂S, and CO₂. By way of example, the stream may include H₂O asone of the one or more contaminants and the gaseous feed stream maycomprise H₂O in the range of 50 parts per million (ppm) molar to 1,500ppm molar; or in the range of 500 ppm to 1,500 ppm molar. Moreover, thefeed stream may include hydrocarbons and H₂O, wherein the H₂O is one ofthe one or more contaminants and the feed stream comprises H₂O in therange of two ppm molar to saturation levels in the feed stream.

In addition, the present techniques may provide an adsorption systemthat utilizes a rapid cycle swing adsorption process to separate acidgas contaminants from feed streams, such as acid gas from hydrocarbonstreams. Acid gas removal technology may be useful for gas reservesexhibit higher concentrations of acid gas (e.g., sour gas resources).Hydrocarbon feed streams vary widely in amount of acid gas, such as fromseveral parts per million acid gas to 90 volume percent (vol. %) acidgas. Non-limiting examples of acid gas concentrations from exemplary gasreserves include concentrations of at least: (a) 1 vol. % H₂S, 5 vol. %CO₂, (b) 1 vol. % H₂S, 15 vol. % CO₂, (c) 1 vol. % H₂S, 60 vol. % CO₂,(d) 15 vol. % H₂S, 15 vol. % CO₂, and (e) 15 vol. % H₂S, 30 vol. % CO₂.Accordingly, the present techniques may include equipment to removevarious contaminants, such as H25 and CO₂ to desired levels. Inparticular, the H₂S may be lowered to levels less than 4 ppm, while theCO₂ may be lowered to levels less than 1.8 molar percent (%) or,preferably, less than 50 ppm. As a further example, the acid gas removalsystem may remove CO₂ to LNG specifications (e.g., less than or equal to50 parts per million volume (ppmv) CO₂).

In certain configurations, the adsorbent material may be used in a rapidcycle swing adsorption process, such as a rapid cycle PSA process, toremove moisture from the feed stream. The specific level may be relatedto dew point of desired output product (e.g., the water content shouldbe lower than the water content required to obtain a dew point below thelowest temperature of the stream in subsequent process and is related tothe feed pressure). As a first approximation, and not accounting forfugacity corrections as a function of pressure, the water concentrationin ppm that yields a certain dew point varies inversely with thepressure. For example, the output stream from the adsorbent bed may beconfigured to be the cryogenic processing feed stream, which satisfiesthe cryogenic processing specifications (e.g., approximately −150° F.(−101.1° C.) dew point for NGL processes or approximately −60° F.(−51.1° C.) for Controlled Freeze Zone (CFZ) processes. The cryogenicprocessing feed stream specification may include a water content in thestream (e.g., output stream from the adsorbent bed or feed stream to theto be cryogenic processing) to be in the range between 0.0 ppm and 10ppm, in the range between 0.0 ppm and 5.0 ppm, in the range between 0.0ppm and 2.0 ppm, or in the range between 0.0 ppm and 1.0 ppm. Theresulting output stream from the adsorbent beds during the purge stepmay include a water content in the stream to be in the range between 0.0ppm and 7 pounds per standard cubic feet (1b/MSCF).

In one or more embodiments, the present techniques can be used for anytype of swing adsorption process. Non-limiting swing adsorptionprocesses for which the present techniques may include pressure swingadsorption (PSA), vacuum pressure swing adsorption (VPSA), temperatureswing adsorption (TSA), partial pressure swing adsorption (PPSA), rapidcycle pressure swing adsorption (RCPSA), rapid cycle thermal swingadsorption (RCTSA), rapid cycle partial pressure swing adsorption(RCPPSA), as well as combinations of these processes, such as pressureand/or temperature swing adsorption. Exemplary swing adsorptionprocesses are described in U.S. Patent Application Publication Nos.2008/0282892, 2008/0282887, 2008/0282886, 2008/0282885, 2008/0282884 and2014/0013955 and U.S. Ser. Nos. 15/233,617; 15/233,623; 15/233,631 and16/233,640, which are each herein incorporated by reference in theirentirety. However, rapid cycle may be preferred to process the stream.However, the adsorbent materials may be preferably utilized with rapidcycle swing adsorption processes.

Further, in certain configurations of the system, the present techniquesmay include a specific process flow to remove contaminants, such aswater (H₂O) or acid gas, in the swing adsoprtion system. For example,the process may include an adsorbent step and a regeneration step, whichform the cycle. The adsorbent step may include passing a feed stream ata feed pressure and feed temperature through an adsorbent bed unithaving an adsorbent material (e.g., adsorebent bed or substantiallyparallel channel contactor) to separate one or more contaminants fromthe feed stream to form a product stream. The feed stream may be passedthrough the substantially parallel channel contactor in a forwarddirection (e.g., from the feed end of the substantially parallel channelcontactor to the product end of the substantially parallel channelcontactor). Then, the flow of the feed stream may be interrupted for aregeneration step. The regeneration step may include one or moredepressurization steps, one or more purge steps and/or one or morere-pressurization steps. The depressurization steps may include reducingthe pressure of the adsorbent bed unit by a predetermined amount foreach successive depressurization step, which may be a single step and/ormay be a blowdown step. The depressurization step may be provided in aforward direction or may preferably be provided in a countercurrentdirection (e.g., from the product end of the substantially parallelchannel contactor to the feed end of the substantially parallel channelcontactor). The purge step may include passing a purge stream into theadsorbent bed unit, which may be a once through purge step and the purgestream may be provided in countercurrent flow relative to the feedstream. The purge product stream from the purge step may be conductedaway and recycled to another system or in the system. Then, the one ormore re-pressurization steps may be performed, wherein the pressurewithin the adsorbent bed unit is increased with each re-pressurizationstep by a predetermined amount with each successive re-pressurizationstep. Then, the cycle may be repeated for additional feed streams and/orthe cycle may be adjusted to perform a different cycle for a secondconfiuguration. The cycle duration may be for a period greater than 1second and less than 600 seconds, for a period greater than 2 second andless than 300 seconds, for a period greater than 2 second and less than200 seconds, or for a period greater than 2 second and less than 90seconds.

Also, the present techniques may be integrated into a variousconfigurations, which may include a variety of compositions for thestreams. Adsorptive separation processes, apparatus, and systems, asdescribed above, are useful for development and production ofhydrocarbons, such as gas and oil processing. Particularly, the providedprocesses, apparatus, and systems are useful for the rapid, large scale,efficient separation of a variety of target gases from gas mixtures. Inparticular, the processes, apparatus, and systems may be used to preparefeed products (e.g., natural gas products) by removing contaminants andheavy hydrocarbons (e.g., hydrocarbons having at least two carbonatoms). The provided processes, apparatus, and systems are useful forpreparing gaseous feed streams for use in utilities, includingseparation applications. The separation applications may include dewpoint control; sweetening and/or detoxification; corrosion protectionand/or control; dehydration; heating value; conditioning; and/orpurification. Examples of utilities that utilize one or more separationapplications include generation of fuel gas; seal gas; non-potablewater; blanket gas; instrument and control gas; refrigerant; inert gas;and/or hydrocarbon recovery.

To provide fluid flow paths through the adsorbent material in anadsorbent bed unit, valve assemblies may include poppet valves, whicheach may include a disk element connected to a stem element which can bepositioned within a bushing or valve guide. The stem element may beconnected to an actuating means, such as actuating means, which isconfigured to have the respective valve impart linear motion to therespective stem. As may be appreciated, the actuating means may beoperated independently for different steps in the process to activate asingle valve or a single actuating means may be utilized to control twoor more valves. Further, while the openings may be substantially similarin size, the openings and inlet valves for inlet manifolds may have asmaller diameter than those for outlet manifolds, given that the gasvolumes passing through the inlets may tend to be lower than productvolumes passing through the outlets. Further, while this configurationhas valve assemblies, the number and operation of the valves may vary(e.g., the number of valves) based on the specific cycle beingperformed.

In one or more embodiments, the rapid cycle swing adsorption processthat utilize the adsorbent materials in the present techniques mayinclude rapid cycle temperature swing adsorption (RCTSA) and/or rapidcycle pressure swing adsorption (RCPSA). For example, the total cycletimes may be less than 600 seconds, less than 300 seconds, preferablyless than 200 seconds, more preferably less than 90 seconds, and evenmore preferably less than 60 seconds.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrative embodiments are only preferred examples of the inventionand should not be taken as limiting the scope of the invention.

What is claimed is:
 1. A cyclical rapid cycle swing adsorbent system forremoving water from a gaseous feed stream, the rapid cycle swingadsorbent system comprising one or more adsorbent bed units that eachcomprise: a housing forming an interior region; a substantially parallelchannel contactor disposed within the interior region of the housing,wherein the substantially parallel channel contactor comprises anadsorbent material being a zeolite 3A having (i) a K to Al atomic ratiois in a range between 0.3 and 1.0; and (ii) a Si to Al atomic ratio isin a range between 1.0 and 1.2; a plurality of valves secured to thehousing, wherein each of the plurality of valves is in flowcommunication with a conduit and configured to control fluid flow alonga flow path extending from a location external to the housing throughthe conduit and to the substantially parallel channel contactor throughthe valve.
 2. The cyclical rapid cycle swing adsorbent system of claim1, wherein the rapid cycle swing adsorption system is configured toperform a rapid cycle pressure swing adsorption process to dehydrate agaseous feed stream.
 3. The cyclical rapid cycle swing adsorbent systemof claim 1, wherein the rapid cycle swing adsorption system isconfigured to perform a rapid cycle temperature swing adsorption processto dehydrate a gaseous feed stream.
 4. The cyclical rapid cycle swingadsorbent system of claim 1, wherein the rapid cycle swing adsorptionsystem is configured to perform a rapid cycle partial pressure swingadsorption process to dehydrate a gaseous feed stream.
 5. The cyclicalrapid cycle swing adsorbent system of claim 1, wherein the rapid cycleswing adsorption system is configured to perform for a cycle durationthat is greater than 2 seconds and less than 300 seconds.
 6. Thecyclical rapid cycle swing adsorbent system of claim 5, wherein therapid cycle swing adsorption system is configured to provide a residencetime for gas in the gaseous feed stream contacting the adsorbentmaterial in the substantially parallel channel contactor during theadsorption step being less than 2.5 seconds.
 7. The cyclical rapid cycleswing adsorbent system of claim 5, wherein the rapid cycle swingadsorption system is configured to provide a residence time for gas inthe gaseous feed stream contacting the adsorbent material in thesubstantially parallel channel contactor during the adsorption stepbeing less than 0.5 seconds.
 8. The cyclical rapid cycle swing adsorbentsystem of claim 1, wherein the adsorbent material has the K to Al atomicratio is in a range between 0.35 and 0.98.
 9. The cyclical rapid cycleswing adsorbent system of claim 1, wherein the adsorbent material hasthe K to Al atomic ratio is in a range between 0.4 and 0.8.
 10. Thecyclical rapid cycle swing adsorbent system of claim 1, wherein theadsorbent material has greater than 80% of the non-potassium cations inthe zeolite 3A are Na.
 11. The cyclical rapid cycle swing adsorbentsystem of claim 1, wherein the adsorbent material has greater than 90%of the non-potassium cations in the zeolite 3A are Na.
 12. The cyclicalrapid cycle swing adsorbent system of claim 1, wherein the adsorbentmaterial is fouling tolerant, wherein fouling tolerant is defined as theadsorbent material having a CO₂ capacity at 25° C. and less than 3minute equilibration times in isotherm measurement of less than 2 millimoles/gram at 760 ton.
 13. The cyclical rapid cycle swing adsorbentsystem of claim 1, wherein the adsorbent material is fouling tolerant,wherein fouling tolerant is defined as the adsorbent material having aCO₂ capacity at 25° C. and less than 3 minute equilibration times inisotherm measurement of less than 0.5 milli moles/gram at 760 torr. 14.The cyclical rapid cycle swing adsorbent system of claim 1, wherein massaverage size of zeolite aggregates in the zeolite 3A are less than 40microns.
 15. The cyclical rapid cycle swing adsorbent system of claim 1,wherein mass average size of zeolite aggregates in the zeolite 3A areless than 10 microns.
 16. The cyclical rapid cycle swing adsorbentsystem of claim 1, wherein mass average size of zeolite aggregates inthe zeolite 3A are less than 5 microns.
 17. A substantially parallelchannel contactor comprising an adsorbent material, wherein theadsorbent material is a zeolite 3A having (i) a K to Al atomic ratio isin a range between 0.3 and 1.0; and (ii) a Si to Al atomic ratio is in arange between 1.0 and 1.2.
 18. The substantially parallel channelcontactor of claim 17, wherein the adsorbent material has the K to Alatomic ratio is in a range between 0.35 and 0.98.
 19. The substantiallyparallel channel contactor of claim 17, wherein the adsorbent materialhas the K to Al atomic ratio is in a range between 0.4 and 0.8.
 20. Thesubstantially parallel channel contactor of claim 18, wherein theadsorbent material has greater than 80% of the non-potassium cations inthe zeolite 3A are Na.
 21. The substantially parallel channel contactorof claim 18, wherein the adsorbent material has greater than 90% of thenon-potassium cations in the zeolite 3A are Na.
 22. The substantiallyparallel channel contactor of claim 17, wherein mass average size ofzeolite aggregates in the zeolite 3A are less than 10 microns.
 23. Thesubstantially parallel channel contactor of claim 17, wherein massaverage size of zeolite aggregates in the zeolite 3A are less than 5microns.
 24. The substantially parallel channel contactor of claim 17,wherein the adsorbent material is fouling tolerant, wherein foulingtolerant is defined as the adsorbent material having a CO₂ capacity at25° C. and less than 3 minute equilibration times in isothermmeasurement of less than 2 milli moles/gram at 760 ton.
 25. Thesubstantially parallel channel contactor of claim 17, wherein theadsorbent material is fouling tolerant, wherein fouling tolerant isdefined as the adsorbent material having a CO₂ capacity at 25° C. andless than 3 minute equilibration times in isotherm measurement of lessthan 0.5 milli moles/gram at 760 torr.